26. Deutsche Physikerinnentagung 2022 (German Conference of Women in Physics)

Nov 24, 2022, 2:00 PM → Nov 27, 2022, 10:30 PM Europe/Berlin

Karlsruhe Institute of Technology

Conference Office (KIT)

 

Thank you all for participating!

Here are some impressions of the conference.

 

The German Conference of Women in Physics (Deutsche Physikerinnentagung), taking place annually since 1997, is supported by the German Physical Society (Deutsche Physikalische Gesellschaft DPG) and by its Working Group on Equal Opportunities (AKC). This year's conference will be hosted by the Karlsruhe Institute of Technology (KIT).

The conference offers female physicists of different areas and at different career levels - from student to professor as well as physicists in industry - the possibility for networking and professional exchange. The program of the conference covers scientific talks from different areas of physics with special focus on the research performed at KIT, the presentation of professional perspectives for physicists, school and didactic events as well as events on topics like equal opportunity, work-life balance, or career management. 

The scientific program will consist of keynote talks and a selection of registered talks. If you are interested in giving a talk (oral or in a poster session) you will have the possibility to send an abstract once the registration will be open. The talks will be selected by the scientific organization committee. You will also have the possibility to register for various workshops and events in due time. 

The conference will take place in person (if the then current Covid rules allow for it). A good part of the program will also be broadcasted online. - Should it turn out that Covid rules will not allow for an in person format in November we will switch to the online format. The majority of the talks and events will be in English (details will be given in due time).

Patron of the conference is Frau Bettina Stark-Watzinger, Federal Minister for Education and Research.

Confirmed speakers include:

• Prof. Cornelia Denz, Physikalisch-Technische Bundesanstalt
• Prof. Monica Dunford, University of Heidelberg
• Prof. Claudia Felser, Director Max-Planck Dresden, Prizewinner of the Max Born Award 2022
• Dr. Elisabeth Fischer-Friedrich, TU Dresden, Prizewinner of the Hertha-Sponer Award 2022
• Prof. Franziska Glassmeier, TU Delft
• Prof. Ramona Gröber, University of Padova
• Dr. Edda Gschwendtner, CERN
• Prof. Céline Hadziioannou, University of Hamburg
• Prof. Stephanie Hansmann-Menzemer, University of Heidelberg
• Prof. Erica Lilleodden, Fraunhofer-Institut für Mikrostruktur von Werkstoffen und Systemen IMWS
• Prof. Roser Valenti, Goethe Universität Frankfurt am Main
• Dr. Belina von Krosigk, Karlsruhe Institute of Technology, Prizewinner of the Hertha-Sponer Award 2023
• Prof. Annette Zippelius, University of Göttingen, Prizewinner of the Max-Planck-Medal 2022

Speakers Schülerinnenprogramm:

• Annika Maier, KIT
• Prof. Dr. Anke-Susanne Müller, IBPT, KIT, Prizewinner of the Landesforschungspreis Baden-Württemberg 2022

For further questions or help contact the local organization committee at dpt2022org@lists.kit.edu.

If you want to support this event please inform yourself about advertising opportunities at the DPT2022 listed in the menu bar 'Sponsoring'.

The following sponsors kindly support the DPT2022:
Robert Bosch GmbH, Bundesamt für die Sicherheit der nuklearen Entsorgung, DESY, d-fine GmbH, HighFinesse GmbH, Leica Microsystems GmbH, Fz Jülich, Infineon Technologies AG, Pfeiffer-Vacuum, Spektrum der Wissenschaft Verlagsgesellschaft mbH, Trumpf SE & Co. KG, xfab, Carl Zeiss AG

                          
       

 

This conference is also supported by: 
CRC TRR 257, CRC 1173, CRC TRR 288, TRR 165, EXC-3DMM2O, KCETA, KSETA, CRC1441, Helmholtz Energy, Institute of Astroparticle Physics (IAP/KIT), Gender Equity 2.

                           

 

The conference is further supported by: 
Exzellenzstrategie des Bundes und der Länder, Deutsche Physikalische Gesellschaft (DPG), Arbeitskreis Chancengleichheit (AKC)

   
     

 

Bulletin.pdf

DPT_ProgramLeaflet_Web.pdf

Preisliste23August2022.pdf

Thursday, November 24

3:30 PM → 5:00 PM Registration and coffee

• Conference badges are handed out
• Coffee and tea can be enjoyed

5:00 PM → 5:30 PM Welcome

5:30 PM → 6:30 PM Opening Lecture: Prof. Stephanie Hansmann-Menzemer, University of Heidelberg

Opening Lecture

DPT_SHM_24112022.pdf

5:30 PM Flavour anomalies - a first glimpse to new physics phenomena?

The world of elementary particles is extremely well
described by the so-called Standard Model of
particle physics, a fundamental quantum field theory.
Despite its huge success in explaining most
of the measurements in our laboratory experiments,
we know that the Standard Model is not complete.
The quest for physics phenomena beyond the Standard
Model is the major topic in present particle
physics. Evidence for tensions with the Standard Model
have been recently accumulated in B hadron decays
involving $b \rightarrow s \ell \ell$ transitions
at the flavour factories LHCb and Belle II. The talk
will summarizes the status of these so-called
flavour anomalies.
Currently the LHC is restarting data taking after
a 3-year long shutdown in which the LHCb experiment
was upgraded to effectively record data at a
significantly increased $pp$ collision rate.
We will report about the commissioning of the upgraded
LHCb experiment and about the plans for the coming data
taking period.

Speaker: Stephanie Hansmann-Menzemer

DPT_SHM_24112022.pdf

6:30 PM → 9:00 PM Reception: Group photo at 19h45

Friday, November 25

7:30 AM → 8:30 AM Commuting by bus: From Campus South to Campus North

9:00 AM → 10:30 AM Physics Talks - Geophysics

9:00 AM Exploration of sub-marine resources using electromagnetic methods

Electromagnetic (EM) methods have proven useful to explore the electrical properties of the earth and are a standard geophysical tool in ground and airborne measurements, but less often in marine applications. The electrical resistivity which can be derived from EM data depends on various rock properties, such as porosity, permeability, mineral content, nature of pore-fluid, or presence of hydrocarbons. In this paper we touch three applications of EM methods for marine resource exploration. The first one is the exploration of seafloor massive sulfides which form as a result of hydrothermal activity at mid-ocean ridges. BGR has developed a customized deep-sea EM platform (Golden Eye) which is used in the German license areas for polymetallic sulfide exploration in the Indian Ocean. The second application is the exploration of submarine gas hydrates, a naturally occurring, solid form of compromised methane gas that forms in continental slope sediments, which is considered as a possible future unconventional energy resource. The third one are offshore aquifers that have formed during the last glacial maximum when sea levels have been about 100 m lower than today. Such fresh water aquifers have been identified in shallow sediments up to 40 km offshore from todays coastlines, and are currently investigates as a sustainable water resource in population-rich und agriculture-intensive coastal regions.

Speaker: Katrin Schwalenberg (Bundesanstalt für Geowissenschaften und Rohstoffe)

Friday_Geophysics_Talk_Schwalenberg.pptx

9:15 AM Effects of seismic anisotropy and attenuation on first-arrival waveforms recorded at the Asse II nuclear repository

For decades, deep geological storage in former salt mines has been a widely recognized strategy for long-term radioactive waste disposal. However, in the case of the Asse II repository in Lower Saxony, groundwater inflow and instabilities in the geological structures rendered the mine unusable as a long-term solution. The nuclear waste needs to be recovered for safety reasons, hence the need for detailed structural information to build a new shaft. In this context, it is essential to use optimized, modern seismic imaging methods, such as, for instance, full-waveform inversion (FWI), to obtain high-resolution, physical parameter models of the Asse salt structure and its surroundings.

The goal of this study is to draw conclusions on the future application of elastic FWI using first-arrival waveforms at frequencies up to 20 Hz, potentially including anisotropy and attenuation. For this purpose, simple parameter models were created based on previously known geological information and used as reference for synthetic forward modeling tests. The objectives were (a) to see if the models are suitable as initial models for FWI, (b) to assess what type of anisotropy needs to be considered, if at all, and (c) to investigate the significance of attenuation. To facilitate the numerical tests, the mathematics of viscoelastic anisotropic wave propagation was studied and a new 2D finite-difference (FD) anisotropic forward solver was implemented.

A detailed comparison of wavefield snapshots and seismograms was conducted between isotropic, vertical-transverse isotropic (VTI), and tilted-transverse isotropic (TTI), as well as elastic and viscoelastic modeling. The results demonstrate that, in general, the models are likely to meet the prerequisites for successfully applying first-arrival FWI up to frequencies of about 20 Hz. While attenuation turned out to be only a minor factor, it is, however, essential to incorporate anisotropy. As the Asse salt structure is complex and steeply dipping, TTI modeling is the preferred way to correctly map the subsurface in high resolution and match first-arrival traveltimes. Furthermore, a comparison with field data acquired over the Asse hill shows that many features present in that data can already be explained using the current approach.

Speaker: Ms Sonia Sortan (KIT Geophysical Institute)

DPT_sonia_sortan.pdf

9:30 AM Seismic Anisotropy Tomography from Glacial Microseismicity: an Antarctic Example

Much of the uncertainty in current prognosis on sea level rise originate from different predictions for the contribution of the West Antarctic Ice Sheet. This contribution is mostly constrained from large-scale ice sheet models, which are designed to understand the ice sheet behaviour in response to external forces. An essential part of such models are flow relations, which relate applied stress and the deformation in the ice. Stress modifies the internal structure of glacial ice through the alignment of individual anisotropic ice crystals. The internal structure of ice, hereafter referred to as ice fabric, then influences the mechanical properties, and therefore the flow pattern of ice streams. Fabric is therefore an important element when modelling ice flow.

Here, we show that shear wave splitting (SWS) of glacial microseismicity can be used to invert for seismic anisotropy and ice fabric at Rutford Ice Stream (RIS). RIS is a fast-flowing Antarctic ice stream, a setting crucial for informing flow models but for which few direct observations of fabric exist.

We present 202,651 SWS measurements from RIS, using three months of data from a 38-station passive seismic network, deployed in 2018/19. Results indicate seismic anisotropy of up to 6.6% in the glacial ice, which has a thickness of ~2.2. km at our study side. However, anisotropy strongly varies depending on azimuth and incidence angle of the seismic rays. We invert the data for depth-dependent ice fabric, making use of the fact that different types of ice fabric can be discriminated against each other based on their anisotropic pattern. The layout of the input models for inversion is designed based on prior knowledge from radar. We find that the following three-layer model fits the data best: a broad vertical cone near the base of RIS (500 m thick), a thick vertical girdle, orientated perpendicular to flow, in the middle (1200 m thick) and a tilted cone fabric in the uppermost 400 m. Such a fabric would cause a depth-dependent strength profile of the ice with the middle layer being harder to deform along flow than across flow. If such a configuration is representative for fast-flowing ice streams, it would call for a more complex integration of viscosity in ice sheet models.

Speaker: Sofia-Katerina Kufner

Kufner_Nov22.pdf

9:45 AM Fiber optic distributed acoustic sensing of local earthquakes at BFO

Distributed acoustic sensing (DAS) measurement, due to high spatial and temporal resolution, has become very attractive in different applications in seismology, for instance seismic noise analysis and seismic event detection. The physical quantity that is measured by DAS is strain or strain rate of optic fiber cable, which is related to the spatial gradient of displacement and velocity that is usually measured by single point seismometers in seismological studies. The amplitude (and signal to noise ratio, SNR) and frequency resolutions of DAS recordings depend on spatial and temporal acquisition parameters, such as i.e. gauge-length (GL) and derivative time (DT), the latter being of importance only if the device records the strain rate. However, coupling of the measurement cable to the ground and the type of the cable are also key parameters affecting the quality of recorded data.

In this study, we show examples of local earthquakes recorded by DAS at the German Black Forest Observatory (BFO), using different cable types and coupling of the cables to the ground. The spectral characteristics of the strain recording of the earthquakes converted from the DAS raw data are studied. The power spectral densities and amplitude of DAS strain data are compared to the strain meter recordings at BFO site as a benchmark, which is recorded using the strain-meter arrays measuring horizontal strain in three different directions independently from the DAS. We concluded about the lower limit of the DAS signal and noise level that is achievable with employing different acquisition parameters, furthermore, we compared spectral content of local earthquakes recorded by DAS at BFO to the recordings of a seismometer.

Speaker: Dr Nasim Karamzadeh Toularoud (Geophysical Institute (GPI), Karlsruhe Institute of Technology (KIT))

Nasim_Karamzadeh.pdf

10:00 AM Distributed seismic sensors for Newtonian Noise Cancellation in Gravitational Wave Detectors

Experiments in fundamental research are becoming more and more sensitive and are often limited by seismic noise and other environmental perturbations. The next generation of gravitational wave detectors on Earth needs to suppress seismic noise by additional 5-6 orders of magnitude (compared to current detectors) to measure gravitational waves at 10Hz emitted by so far unresolved cosmological binary objects. Below 10Hz, a new threshold is reached where mass changes in the Earth caused by seismic noise will exert a gravitational pull on the detectors limiting the gravitational wave measurement. This so-called Newtonian noise cannot be shielded due to its gravitational nature and other methods, such as coherence noise cancellation systems, must be developed. In this presentation, we will look at the sensor types and techniques proposed for Newtonian Noise Cancellation and the benefits of developing new optical distributed seismic fiber sensors, not only for gravitational wave detection but also for geophysics and seismology.

Speaker: Katharina-Sophie Isleif (Helmut-Schmidt-University)

20221125_KSI_PT22_DI-Seismic_Sensors.pdf

9:00 AM → 10:30 AM Physics Talks - Solid State Theory

9:00 AM Building Blocks for Cluster Mott Insulators

The Hubbard model provides a playground for investigating the physics of a wide range of strongly correlated systems. An important feature of these systems is the Mott insulator phase, where at half-filling, an electron gets localised on a single lattice site. In this work, we extend the idea to cluster Mott insulators-- where an electron is now localised on clusters of sites. To that end, we study the Hubbard model on a plethora of two-dimensional clusters, at different select fillings. Since strong electron correlations often occur in proximity to a Mott insulating state, we write down a general interaction term for such a cluster Mott insulator. We then explore different regimes of the interplay of strong correlations and hopping within these clusters, and their respective effective degrees of freedom. It is also possible to go beyond the single-orbital ``cluster" Hubbard model and include multiple orbitals and/or interactions among them. This makes it closer to real materials. Once a blueprint for these building blocks has been established, they can be connected through inter-cluster terms, giving rise to novel Hamiltonians.

Speaker: Vaishnavi Jayakumar (Insitute for Theoretical Physics, University of Cologne, Germany)

Vaishnavi_Jayakumar_Building_Blocks_for_Cluster_Mott_Insulators.pdf

9:15 AM Magnetic states and high-pressure enthalpy landscape of manganese sulfide polymorphs: a first-principles study

We combine density functional theory (DFT) with special quasirandom structures (QRS) and occupation control matrix (OCM) methods to investigate the magnetic ordering and pressure effects on manganese sulfide polymorphs. MnS is usually found in paramagnetic (PM) rock-salt (RS) structure under ambient conditions, but it becomes antiferromagnetic (AFM) as temperature decreases at constant pressure. On the other hand, at room temperature, it has been observed that MnS undergoes pressure induced structural transformations. Our study shows that by taking into account the ordering/disordering of the local magnetic moments and the explicit control of the Mn 𝑑-electrons' localization, the computed energy bandgaps and local magnetic moments are in excellent agreement with those reported experimentally, particularly for PM-MnS.
Finally, by studying the enthalpy landscape of various MnS polymorphs, we identify at about 21  GPa, the structural transformation from RS to orthorhombic MnP-type. This structural transformation seems to explain previously reported experimental results of a new stable but unidentified MnS phase at similar pressure.

Speaker: Prof. Maribel Núñez-Valdez (Helmholtz Zentrum Potsdam (GFZ)/Goethe University Frankfurt am Main)

Women_in_Physics_Karlsruhe_Nov2022_MNV.pdf

9:30 AM Analogues of light and gravity in the collective excitations of quantum magnets

Condensed matter systems can possess striking parallels with gauge theories that arise in the context of high-energy physics, exemplified by the Anderson-Higgs transition in superconductors [1], and emergent photons [2] and magnetic monopoles [3] in spin ice. Such examples raise the question of where else there is potential for low-energy experiments to inform physics relevant to high-energy scales.

Here, we present two further parallels that exist between the excitations of magnetic systems and two of nature's fundamental gauge theories, namely electrodynamics and general relativity.

We first review the connection between the Goldstone modes of a Néel antiferromagnet and the photons of electromagnetism. Then, motivated by results from simulation, we present a mapping between the linearly dispersing Goldstone modes of a system with ferroquadrupolar (spin-nematic) order and gravitational waves in flat space, as described within the framework of linearized gravity. Our results suggest that the massless spin-2 excitations of spin-nematic phases could provide a low-energy analogue of gravitational waves.

[1] P. W. Anderson, Phys. Rev. 130, 439 (1963).
[2] O. Benton, O. Sikora and N. Shannon, Phys. Rev. B 86, 075154 (2012).
[3] C.Castelnovo, R. Moessner and S. L. Sondhi, Nature 451, 42-45 (2008).

Speaker: Ms Leilee Chojnacki (OIST)

20221124-short-talk-v1.pdf

9:45 AM Quantum critical Eliashberg theory in a finite dimensional SYK model

We present a model of superconductivity in a higher dimensional generalization of the Sachdev-Ye-Kitaev model. In the normal state this model features a critical phase in (1+1) dimensions and a quantum phase transition in (2+1) dimensions. For (2+1) dimensions the superconductivity emerges around the quantum critical point. We derive the Eliashberg equations of superconductivity from the saddle point equations of the field theory in the limit of a large number of degrees of freedom. Finally we analyse the effect of pair-breaking and tuning of the boson to fermion flavour ratio on the superconducting phase.

Speaker: Veronika Stangier (KITI)

Stangier_DPT22.pdf

10:00 AM Influence of Coulomb correlations on high harmonic generation in monolayer TMDC materials

The nonlinear optical phenomenon of high harmonic generation (HHG) in solid state materials was employed to study different properties of these materials. In a wide range of semiconducting materials, HHG can be induced by off-resonant excitation with ultrashort strong-files pulses in the THz- and mid-IR-range. The study of HHG in TMDC materials has been shown to be particulary interesting due to their strong non optical nonlinearities and the complex interplay of their directional-, spin- and valley-selective emission characteristics (see e.g. [1,2]).

Furthermore, the material thinness of TMDC monolayers causes strong Coulomb interactions that goes hand in hand with a high sensitivity to the dielectric surrounding and the excitation conditions. The presence of excited carriers induces a screening of the Coulomb interaction resulting in a renormalization of the band structure. For pulses that are shorter than the de-coherence time, these carrier distributions vanish with the pulse induced polarizations. Thus, one should expect ultrafast signatures of Coulomb screening and the related field and energy renormalizations in the HHG signal.

Here, we employ a microscopic approach combining DFT with a Semiconductor-Bloch equation approach to investigate the influence of Coulomb correlations on HHG in TMDC monolayers. Based on the DFT single-particle band structure and the phase-corrected dipole matrix elements, we derive an effective two-dimensional model that allows to include all relevant Coulomb effects.

[1] H. Liu, et al., Nature Phys 13, 262–265 (2017).
[2] Y. Kobayashi, et al., Ultrafast Science, 2021, 9820716 (2021).

Speaker: Josefine Neuhaus

9:00 AM → 10:30 AM Physics and Profession 1

9:00 AM Fusing physics, entrepreneurship and family

In this talk I would like to give you some insights into the founding history of HQS Quantum Simulations GmbH and my job as Co-Founder and COO. HQS, founded in 2017, aims to bridge the gap between research and industry in the field of quantum computing. We develop software for conventional computers and quantum computers to exploit the immense potential of quantum level simulations to accelerate the development of new materials in the chemical, pharmaceutical, and materials industry. I completed my Ph.D. in Physics at Karlsruhe Institute of Technology in 2018. Shortly before HQS was founded, my first child was born and my PhD was not yet completed. In my talk I will explain why I have chosen this path under these circumstances.
As COO, I'm now responsible for efficient business operations and organizational development and for the development of the customer-facing software. My role allows me to work in an extremely interesting field with interesting people while at the same time helping to shape our working environment. My physics degree allows me to familiarize myself very quickly with new topics, both in the field of technology and in entrepreneurial topics. This allows for fast and focused decision making even in a very dynamic environment, which is essential to move our company forward.

Speaker: Iris Schwenk (HQS Quantum Simulations GmbH)

9:30 AM From b-Tagging to the Autonomous Supply Chain – a career outside of Physics

Johanna is currently working as Product Director at Blue Yonder, a software company providing supply chain and retail planning offerings. Johanna completed her physics degree at the University of Mainz, and did her PhD at CERN working on the ATLAS experiment. After finishing her degree, Johanna started working for Blue Yonder as a Data Scientist, Project Manager and now as Product Director. She is currently responsible for Blue Yonder’s supplier ordering solution in retail, from understanding customer requirements, working with User Experience designers on new workflows and implementing them together with the development teams. In her career she works with experts around the globe, to understand complex process workflows and to abstract them into a product solution.

Speaker: Johanna Fleckner-Barber (Blue Yonder GmbH)

JohannaFlecknerBarber_PhysikerinnenTagung_2022.pdf

10:00 AM Towards fully autonomous robotics: a physicist's view

In order to interact safely with the physical world, an autonomous system needs to be able to sense, perceive, plan and act. Research and development of algorithms that enable this kind of intelligent decision-making in robots operating in unstructured, dynamic environments is a task that lies at the intersection of mathematics, physics, computer science and mechanical engineering.

As a postdoctoral researcher and project lead in the field robotics team of the group "Optimization and Optimal Control" at the University of Bremen, my work involves close collaboration with industry partners to develop algorithms for autonomous robots and apply them to real prototypes. In this talk, I would like to provide insights into the challenges we face on our way to creating fully autonomous systems, the role that a sound understanding of physics and mathematics plays in being able to find solutions to them, and finally into my career path from theoretical physics to robotics.

After completing my masters in physics at the Indian Institute of Technology, Madras, I came to DESY Hamburg for my PhD in particle physics phenomenology, following which I continued in particle physics as a postdoc at the Karlsruhe Institute of Technology. Wanting to transition to the industry but not yet willing to fully leave research, I now work at the Center for Industrial Mathematics at University of Bremen, where I have been a postdoctoral researcher since 2020.

Speaker: Shruti Patel (University of Bremen)

9:00 AM → 10:30 AM Workshop 1 (offline only): “Selbstmarketing für Wissenschaftlerinnen“: Morning

Trainer: Ines Köhler

Dass Selbstmarketing immer wichtiger wird, um die eigene Forschung bekannter zu machen, ist den Meisten in der akademischen Welt längst klar. Viele stehen aber dennoch vor der Frage, wie genau man das nun am besten angeht und worauf es – insbesondere als Frau – zu achten gilt. Der Workshop bietet die Möglichkeit, sich mit diesem Thema in einer Peer Group stärker auseinanderzusetzen, und gibt Tools und Ressourcen an die Hand, um sich als Forscherin selbstbewusst und effektiv zu präsentieren.

Target groups: female PhD candidates, female postdocs

10:30 AM → 11:00 AM Coffee break

• coffee and tea can be enjoyed

11:00 AM → 11:45 AM Keynote Physics Talks 1: Geophysics - Prof. Céline Hadziioannou, University of Hamburg

Keynote

11:00 AM How can seismological observations inform us about physical processes across the scales?

The ambient seismic wave field carries information about the sources that excited it, and about the material that it passed through. By recording and carefully analyzing the seismic ‘background noise’, we can learn many things about physical processes on Earth and beyond.

For example, the most prominent seismic noise comes from interactions between ocean waves and the solid Earth. Therefore, it carries the imprint of storms, of weather over the oceans and seas, and even of the tides.

The seismic noise field also carries the imprint of structures it has passed through, and changes therein. I will show that useful signals can be extracted from ambient noise, which can then be used to monitor material changes with high temporal resolution.

Thanks to recent sensor developments, we can use telecommunication fiber for seismo-acoustic measurements with unprecedented spatial and temporal resolution. This type of measurement offers high potential for seismic measurements to support high precision physical experiments, accelerators, and gravitational wave detectors.

Over the past decade, the use of seismic noise has found its way into applications across temporal and spatial scales. I will give an overview of current applications as well as a quick peek into future developments.

Speaker: Celine Hadziioannou

2022_hadziioannou_DPT_seismology.pdf

11:00 AM → 11:45 AM Keynote Physics Talks 2: Solid State Experiment - Prof. Claudia Felser, Director Max-Planck-Institute Dresden

Keynote

11:00 AM Topology and Chirality

Topology, a well-established concept in mathematics, has nowadays become essential to describe condensed matter. At its core are chiral electron states on the bulk, surfaces and edges of the condensed matter systems, in which spin and momentum of the electrons are locked parallel or anti-parallel to each other. Magnetic and non-magnetic Weyl semimetals, for example, exhibit chiral bulk states that have enabled the realization of predictions from high energy and astrophysics involving the chiral quantum number, such as the chiral anomaly, the mixed axial-gravitational anomaly and axions. The potential for connecting chirality as a quantum number to other chiral phenomena across different areas of science, including the asymmetry of matter and antimatter and the homochirality of life, brings topological materials to the fore.

Speaker: Prof. Claudia Felser (Max Planck Institute for Chemical Physics of Solids)

DPT 2022.pptx

DPT 2022.zip

11:00 AM → 12:30 PM Workshop 1 (offline only): “Selbstmarketing für Wissenschaftlerinnen“: Noon

Trainer: Ines Köhler

Dass Selbstmarketing immer wichtiger wird, um die eigene Forschung bekannter zu machen, ist den Meisten in der akademischen Welt längst klar. Viele stehen aber dennoch vor der Frage, wie genau man das nun am besten angeht und worauf es – insbesondere als Frau – zu achten gilt. Der Workshop bietet die Möglichkeit, sich mit diesem Thema in einer Peer Group stärker auseinanderzusetzen, und gibt Tools und Ressourcen an die Hand, um sich als Forscherin selbstbewusst und effektiv zu präsentieren.

Target groups: female PhD candidates, female postdocs

11:45 AM → 12:30 PM Keynote Physics Talks 1: Meteorology - Prof. Franziska Glassmeier, TU Delft

Keynote

11:45 AM Aerosol-cloud-climate cooling as a data-driven dynamical system

Anthropogenic drivers of the climate system not only include greenhouse gases but also particulate air pollution. These anthropogenic aerosols exert a net cooling effect so that they partially mask greenhouse-gas warming. The magnitude of this effect is a major uncertainty for climate projections. The dominant mechanism behind this uncertainty is the response of clouds to aerosol perturbations, especially of cloud decks over the subtropical oceans. These clouds cool the planet by reflecting sunlight back to space and aerosols modulate their reflectivity and amount. We will discuss how the dynamics of cloud decks can be characterized as a data-driven dynamical system. Our emphasis will lie on the role of different timescales of the cloud response to aerosols, and why “opportunistic experiments” like the bright tracks that ship exhaust can create in overlying cloud decks do not tell the whole story of aerosol-cloud climate cooling.

Speaker: Franziska Glassmeier

11:45 AM → 12:30 PM Keynote Physics Talks 2: Solid State Theory - Prof. Roser Valenti, University of Frankfurt

Keynote

11:45 AM Quantum materials design: challenges and opportunities

Unconventional superconductivity with high critical temperatures, frustrated magnetism, spin-liquid phases or the recently discussed Kitaev phases are a few examples of exotic states in correlated quantum materials.
One of the big challenges in quantum physics is the microscopic description of such materials. Moreover, being able to understand them implies the possibility of predicting compounds with desirable properties.
In this talk, I will present and discuss strategies for designing quantum materials from first principles and their connection to experimental observations.

Speaker: Prof. Roser Valenti (Goethe University Frankfurt)

12:30 PM → 2:00 PM Lunch break 1

12:30 PM → 2:00 PM Lunch break 2

12:30 PM → 2:00 PM Lunch break 3

2:00 PM → 2:30 PM Guided tour 1: "KATRIN Experiment: measuring the neutrino mass with the world’s most sensitive scale": 1. Group

Access restrictions: No active biomedical implants allowed

We invite you to visit the KArlsruhe TRItium Neutrino (KATRIN) Experiment located at KIT Campus North.
KATRIN is an international project for fundamental research. Its goal is to measure the neutrino mass by precisely analysing the beta-electron spectrum of tritium. Neutrinos are the most abundant particle species in the universe. They are described in the standard model of elementary particles as being massless. However, observations of solar and atmospheric neutrinos have led to the conclusion that neutrinos indeed carry a tiny, but non-zero mass. In order to determine this mass KATRIN uses a high-luminosity tritium source and a spectrometer with 10m in diameter. With this experimental setup KATRIN holds the world-best current limit on the neutrino mass of 0.8 eV at 90% confidence level and is continuing to take data for a target sensitivity of 0.2 eV.
More information can be found on our webpage.

2:00 PM → 3:00 PM Guided tour 2: "KARA and FLUTE: the KIT particle accelerators": Group 1

Access restrictions: None

Come visit the particle accelerators developed and operated by the Institute of Beam Physics and Technology (IBPT) at KIT!
The research infrastructure Karlsruhe Research Accelerator (KARA) provides a 2.5-GeV storage ring and light source for experiments with electron beams and intense synchrotron radiation for deep insights into matter, biological structures, and materials.
The FLUTE facility (name abbreviation derived from its German name: Ferninfrarot Linac- und Test-Experiment) is a linear accelerator that will provide coherent radiation in ultra-short, very intense, light pulses spanning the terahertz and far-infrared spectral range and beyond.
More information can be found on our webpage.

2:00 PM → 2:30 PM Guided tour 3: "The High Performance Computer HoreKa at Steinbuch Centre for Computing (SCC)": Group 1

SCC operates large-scale research equipment and large-scale research infrastructures at KIT Campus North and Campus South. This visit concerns the High Performance Computer Horeka, which was among the 15 most powerful computers in Europe when it was commissioned in mid-2021. HoreKa can provide a computing power of approximately 17 PetaFLOPS. The system is available to scientists from all over Germany.
More information can be found on the webpage of SCC.

2:00 PM → 3:00 PM Keynote Gender Talks 1: Jess Wade, Imperial College London

2:00 PM How can early career researchers contribute to the fight for equity?

Despite women leading the development of the Moderna, Astra Zeneca and Johnson & Johnson COVID-19 vaccines, the majority of adults cannot name a woman scientist. That’s not entirely surprising given the national curriculum for science doesn’t include a single woman’s name. Jess will talk about how who we talk about matters, and the importance of science communication and awareness of the universality of (historic and present) scientific contributions for global human development. She’ll also discuss her efforts to increase visibility of scientists from historically marginalised groups on Wikipedia, her research in materials science and nanotechnology, the power of social media for early career researchers and her new picture book ‘Nano, the Spectacular Science of the Very (Very) Small’.

Speaker: Dr Jess Wade (Imperial College London)

2:00 PM → 4:00 PM Workshop 2 (online only): "Self-marketing: Putting your best self forward": Afternoon

This workshop will take place exclusively online via zoom!

Trainer: Francesca Carlin

Self-marketing has become more and more important in this day and age, but there is very little guidance and resources on the best practices for academics. In addition, women in academia face challenges that their male-counterparts do not when it comes to marketing and visibility. This workshop aims to provide female academics with the tools and resources to enable them to market themselves effectively and with confidence.

Target groups: female PhD candidates, female postdocs

2:30 PM → 3:00 PM Guided tour 1: "KATRIN Experiment: measuring the neutrino mass with the world’s most sensitive scale": 2. Group

Access restrictions: No active biomedical implants allowed

We invite you to visit the KArlsruhe TRItium Neutrino (KATRIN) Experiment located at KIT Campus North.
KATRIN is an international project for fundamental research. Its goal is to measure the neutrino mass by precisely analysing the beta-electron spectrum of tritium. Neutrinos are the most abundant particle species in the universe. They are described in the standard model of elementary particles as being massless. However, observations of solar and atmospheric neutrinos have led to the conclusion that neutrinos indeed carry a tiny, but non-zero mass. In order to determine this mass KATRIN uses a high-luminosity tritium source and a spectrometer with 10m in diameter. With this experimental setup KATRIN holds the world-best current limit on the neutrino mass of 0.8 eV at 90% confidence level and is continuing to take data for a target sensitivity of 0.2 eV.
More information can be found on our webpage.

2:30 PM → 3:00 PM Guided tour 3: "The High Performance Computer HoreKa at Steinbuch Centre for Computing (SCC)": Group 2

SCC operates large-scale research equipment and large-scale research infrastructures at KIT Campus North and Campus South. This visit concerns the High Performance Computer Horeka, which was among the 15 most powerful computers in Europe when it was commissioned in mid-2021. HoreKa can provide a computing power of approximately 17 PetaFLOPS. The system is available to scientists from all over Germany.
More information can be found on the webpage of SCC.

3:00 PM → 3:30 PM Guided tour 1: "KATRIN Experiment: measuring the neutrino mass with the world’s most sensitive scale": 3. Group

Access restrictions: No active biomedical implants allowed

We invite you to visit the KArlsruhe TRItium Neutrino (KATRIN) Experiment located at KIT Campus North.
KATRIN is an international project for fundamental research. Its goal is to measure the neutrino mass by precisely analysing the beta-electron spectrum of tritium. Neutrinos are the most abundant particle species in the universe. They are described in the standard model of elementary particles as being massless. However, observations of solar and atmospheric neutrinos have led to the conclusion that neutrinos indeed carry a tiny, but non-zero mass. In order to determine this mass KATRIN uses a high-luminosity tritium source and a spectrometer with 10m in diameter. With this experimental setup KATRIN holds the world-best current limit on the neutrino mass of 0.8 eV at 90% confidence level and is continuing to take data for a target sensitivity of 0.2 eV.
More information can be found on our webpage.

3:00 PM → 4:00 PM Guided tour 2: "KARA and FLUTE: the KIT particle accelerators": Group 2

Access restrictions: None

Come visit the particle accelerators developed and operated by the Institute of Beam Physics and Technology (IBPT) at KIT!
The research infrastructure Karlsruhe Research Accelerator (KARA) provides a 2.5-GeV storage ring and light source for experiments with electron beams and intense synchrotron radiation for deep insights into matter, biological structures, and materials.
The FLUTE facility (name abbreviation derived from its German name: Ferninfrarot Linac- und Test-Experiment) is a linear accelerator that will provide coherent radiation in ultra-short, very intense, light pulses spanning the terahertz and far-infrared spectral range and beyond.
More information can be found on our webpage.

3:00 PM → 3:30 PM Guided tour 3: "The High Performance Computer HoreKa at Steinbuch Centre for Computing (SCC)": Group 3

SCC operates large-scale research equipment and large-scale research infrastructures at KIT Campus North and Campus South. This visit concerns the High Performance Computer Horeka, which was among the 15 most powerful computers in Europe when it was commissioned in mid-2021. HoreKa can provide a computing power of approximately 17 PetaFLOPS. The system is available to scientists from all over Germany.
More information can be found on the webpage of SCC.

3:00 PM → 4:00 PM Keynote Gender Talks 1: Andrea Bossmann, TU Berlin

3:00 PM Gender within the culture of physics

Research in physics is supposed to be objective: physicists perform experiments and measurements, mathematical derivations, or numerical simulations. The methods as well as the research objects don't have a gender.

At the same time we observe that still today the vast majority of physicists are (white) men. Why is it like this? And what implications does this have? This talk will give an overview of the current state of research of gender and diversity studies in physics. I will highlight what we can learn from gender studies about the social context of our research practice and the everyday workplace culture in physics. Furthermore, I will address insights from the comparison with the situation in other countries and which approaches and strategies may help improve the situation.

Speaker: Andrea Bossmann (TU Berlin)

3:30 PM → 4:00 PM Guided tour 1: "KATRIN Experiment: measuring the neutrino mass with the world’s most sensitive scale": 4. Group

Access restrictions: No active biomedical implants allowed

We invite you to visit the KArlsruhe TRItium Neutrino (KATRIN) Experiment located at KIT Campus North.
KATRIN is an international project for fundamental research. Its goal is to measure the neutrino mass by precisely analysing the beta-electron spectrum of tritium. Neutrinos are the most abundant particle species in the universe. They are described in the standard model of elementary particles as being massless. However, observations of solar and atmospheric neutrinos have led to the conclusion that neutrinos indeed carry a tiny, but non-zero mass. In order to determine this mass KATRIN uses a high-luminosity tritium source and a spectrometer with 10m in diameter. With this experimental setup KATRIN holds the world-best current limit on the neutrino mass of 0.8 eV at 90% confidence level and is continuing to take data for a target sensitivity of 0.2 eV.
More information can be found on our webpage.

3:30 PM → 4:00 PM Guided tour 3: "The High Performance Computer HoreKa at Steinbuch Centre for Computing (SCC)": Group 4

SCC operates large-scale research equipment and large-scale research infrastructures at KIT Campus North and Campus South. This visit concerns the High Performance Computer Horeka, which was among the 15 most powerful computers in Europe when it was commissioned in mid-2021. HoreKa can provide a computing power of approximately 17 PetaFLOPS. The system is available to scientists from all over Germany.
More information can be found on the webpage of SCC.

4:00 PM → 4:30 PM Coffee break

4:30 PM → 6:00 PM Gender Projects: Geschichte von AKC und DPT / Physik-Projekt-Tage

4:30 PM Die Geschichte von AKC und DPT

Mit diesem Beitrag stellen wir Euch den Arbeitskreis Chancengleichheit (AKC) vor, eine fachübergreifende Vereinigung innerhalb der Deutschen Physikalischen Gesellschaft (DPG) mit über 690 Mitgliedern. Das Ziel des AKC ist die Verbesserung der Rahmenbedingungen und Strukturen für Frauen in der Physik zur Erreichung von Chancengleichheit in Ausbildung und Beruf. Hierzu gehört auch die jährlich stattfindende Physikerinnentagung. Die Tagung stellt eine Plattform zum Kennenlernen und Austausch dar, und sie erhöht so die Sichtbarkeit von Physikerinnen. Im Vortrag geben wir einen Überblick über die Geschichte des AKCs und der DPT von der Idee über die Gründung bis zum heutigen Zeitpunkt. Dabei zeigen wir zahlreiche Meilensteine auf, beginnend mit der Schaffung des AKCs und der DPT. Wir benennen die vielfältigen Aufgaben, die unsere Kommission und ihre Unterstützerinnen bearbeiten. Für die Gestaltung der Zukunft brauchen wir Euch, bitte teilt uns Eure Meinung, Wünsche und Ziele mit.

Speaker: Agnes Sandner (AKC)

5:30 PM Physik-Projekt-Tage – Gleichstellung in der Physik an Hand eines Workshops nur für Schülerinnen

Dass Gleichstellungsarbeit besonders in der Physik ein wichtiges Thema ist, zeigen nicht zuletzt die Einschreibezahlen von Studentinnen in den Physikstudiengängen. In Kiel liegt der Prozentsatz von Frauen bei etwa 15%. Um ein angemessenes Geschlechterverhältnis auf allen Karrierestufen zu erreichen genügt es daher nicht, erst an der Universität mit Gleichstellungsarbeit zu beginnen - es muss bereits in der Schule angesetzt werden. Mit den Physik-Projekt-Tagen (PPT) wurde ein viertägiger Workshop nur für Schülerinnen ins Leben gerufen. Die Teilnehmerinnen haben die Möglichkeit, zu Schuljahresbeginn vier Tage lang in einem Projekt ihrer Wahl zu experimentieren, ihr Interesse an Physik zu steigern und Netzwerke über Schulgrenzen hinweg aufzubauen. 
Die Projekte umspannen verschiedene Forschungsfelder der Physik und reichen von Teilchenphysik, über Laserphysik und Plasmaphysik bis hin zu Nanowissenschaften. Zur Qualitätssicherung und Weiterentwicklung dieser Veranstaltung werden die PPT von einer kritischen Evaluation begleitet. Das Konzept der PPT, Inhalte und ausgesuchte Ergebnisse der Evaluation werden vorgestellt. Seit 2015 ist das Projekt im Instrumentenkasten für Gleichstellungsarbeit der DFG.

Speaker: Dr Anna Benecke (UC Louvain)

PPT_DPT2022_Karlsruhe.pdf

4:30 PM → 6:00 PM Physics Talks - Meteorology and Atmospheric Physics

4:30 PM Why can we trust climate model simulations of ozone depletion chemistry?

The ozone layer is a protective layer of gas in the stratosphere between 15 and 35km that absorbs most harmful solar UV radiation before it reaches the Earth’s surface. In the 1970s, it was discovered that reactive inorganic chlorine gases in the stratosphere catalyze ozone depletion in the springtime. In response, the use of industrial chlorine sources has been phased out by the 1987 Montreal Protocol and its subsequent amendments, allowing ozone recovery to begin. A significant amount of inorganic chlorine remains in the atmosphere in the form of inert “reservoir” species (e.g. HCl, ClONO2, and HOCl) and reactive “radical” species (e.g. ClO and Cl). These gases make up the total inorganic chlorine chemical family, Cly. The extent of Cly’s impact on ozone in any given year is heavily influenced by how the total amount of inorganic chlorine is “partitioned”, or divided, between these radical and reservoir species. Therefore, climate models must be able to simulate chlorine partitioning accurately in order to predict the recovery of the ozone layer. To this end, we use a combination of spectroscopic satellite measurements to investigate the Canadian Middle Atmosphere Model’s ability to capture chlorine partitioning and ozone depletion. This type of assessment provides insight into the model’s strengths and limitations, which is crucial for future model improvements and model-based studies on the evolution of ozone layer recovery.

Speaker: Laura Saunders

DPT_LSaunders.pdf

4:45 PM Mixed-phase clouds: a journey between observations and climate models

In numerical weather prediction and climate models a particular challenge is represented by the simulation of mixed-phase clouds. These clouds occur in a temperature range between 0°C and -38°C, their hydrometeors can either consist of supercooled water or of ice, and the coexistence of both is very likely. The partitioning into liquid and ice in this regime depends on many factors (e.g. cloud dynamics, aerosols as ice nuclei, ice multiplication processes...) and varies therefore depending on cloud types, regions and seasons. To adress this complex problem, we first analyse observations, followed by the comparison of the findings with the climate models outputs. We use four years satellite data observations (from 1 June 2009 to 31 May 2013) to analyse the cloud phase distribution under different conditions. Several datasets are used to investigate the liquid and ice cloud distribution in order to account for uncertainties in the observations. The considered datasets are based on passive and active sensors on-board polar orbiting satellites.
In our analysis, special attention is paid to the geographical distribution of different cloud types and how the supercooled liquid fraction (SLF) in each cloud type is related to the temperature. The cloud types are assigned according to a cloud classification based on “cloud top pressure - cloud optical thickness” joint histograms. Despite temperature and phase mismatches between the datasets, systematic dependencies of the supercooled liquid fraction versus temperature are found comparing the different cloud types at different height and in separate latitude bands: in particular, SLF is larger in the Southern Hemisphere than in the Northern Hemisphere, except for the continental low-level clouds, for which the opposite occurs.
Other results show the importance of the atmospheric boundary layer and, presumably, of the aerosol distribution for the mixed-phase clouds: While the high-level clouds present similar patterns comparing them over continental/maritime regions and for Northern/Southern Hemispheres, low- and mid-level clouds show regional dependencies.
Initial results from the analysis of global climate models reveal good agreement between observations and models when comparing how SLF changes with the temperature, while remarkable differences are found on how the size of the liquid cloud droplet effective radius change with SLF for different cloud types and over different regions.

Speaker: Olimpia Bruno (KIT)

DPT2022_OlimpiaBruno.pdf

5:00 PM Microphysical Pathways Active within Thunderstorms and Their Sensitivity to CCN Concentration and Wind Shear

Previous studies have obtained contradicting results on the impact of Cloud condensation nuclei (CCN) concentration on microphysical processes within thunderstorms and the resulting surface precipitation. In this work, an analysis of the ``microphysical pathways'' occurring in these clouds, with a particular emphasis on the formation of large hail and heavy precipitation, is proposed to systematically investigate and understand these sensitivities.

Thunderstorms were simulated using convection-permitting (1 km horizontal grid spacing) idealised simulations with the ICON model, which included the Seifert and Beheng 2-moment microphysics parameterization. CCN concentrations were increased from 100 to 3200 CCN/cm3, in five different wind shear environments ranging from 18 to 50 m/s. Large and systematic decreases of surface precipitation (up to 35%) and hail (up to 90%) were found as CCN was increased. Wind shear changes the details, but not the sign, of the sensitivity to CCN. These decreases result from microphysical processes becoming less efficient at forming precipitation and not from changes to the updraft.

The microphysical process rates were tracked throughout each simulation, allowing the mass budget to be closed for each hydrometeor class. The microphysical processes were collected together into ``microphysical pathways'', which describe and quantify the different growth processes leading to surface precipitation (see Figure). Almost all surface precipitation occurred through the mixed-phase pathway, where graupel and hail grow by riming and later melt as they fall to the surface. The mixed-phase pathway is also sensitive to CCN concentration changes, as a result of changes to the riming rate. Potential causes for the riming rate changes were systematically evaluated. Supercooled water content was almost insensitive to increasing CCN concentration, but decreased cloud drop size led to a large reduction in the riming efficiency (from 0.79 to 0.24) between supercooled cloud drops and graupel or hail. Therefor the graupel and hail stones grow more slowly, reach smaller sizes and are less likely to reach the surface. Additional simulations using a constant collection efficiency (either 0.5 or 1.0) for all cloud drop sizes removed the systematic sensitivity of precipitation to CCN concentration, but hail remained sensitive to CCN due to differences in hail embryo formation pathways.

Speaker: Prof. Corinna Hoose (KIT)

Barrett_Hoose_HailCCN_DPT2022.pdf

5:15 PM Further characteristics of the atmospheric turbulent wind: Periods of constant wind speed and waiting times between gusts

The loads affecting an operating wind turbine are estimated using numerical simulations that aim to reproduce the real interactions between the turbine and the incoming wind. Then, accurate descriptions of both, the physical turbine and the atmospheric wind, to be included in the numerical estimations are essential in the design, manufacturing and operation processes of a wind turbine. Particularly, the characterization of the atmospheric turbulent wind is currently performed based on the standard guideline proposed by the International Electrotechnical Commission (IEC 61400-1). Although this guideline accounts for essential descriptions of the atmospheric wind, some further statistical characteristics have been poorly addressed. As a result, operating wind turbines might react unpredictably to such structures that have not been properly identified and parametrized from atmospheric data and later included within the numerical models. In this work, we introduce and parametrize two additional features from the atmospheric turbulent wind that have not been considered by the current IEC guideline: the periods of constant wind speed $(T_c)$ and waiting times between wind gusts $(T_{g})$. We hypothesize that certain conditions of these events on the wind might induce unexpected dynamic responses in the turbine. Therefore, we focus on the statistical description of those features on the wind in terms of their magnitude, probability of occurrence and possible extreme events.

The probability distributions $p(T_{c})$ and $p(T_{g})$ exhibit a power-law decay. From an engineering perspective, very long periods of constant wind speed $T_c$ might be undesirable for an operating wind turbine. As an example, if a such long event is located on a specific area of the rotor plane, it may lead to unexpected periodic loads resulting from the blade passing through the constant speed structure at the given location on the plane. On the other hand, the time between two consecutive large increments might be of high relevance for the dynamic response of the wind turbine. Specific times $T_{g}$ that coincide with the characteristic frequencies of the turbine, might either intensify or diminish oscillations of the structure. Consequently, in combination with the characterization of features such as $T_{c}$ and $T_{g}$, it is essential to investigate the impact of those structures carried by the wind on the response of the wind turbine.

Results from a preliminary study on the effect of the magnitude of $T_{g}$ on numerically simulated loads showed that the variation in the waiting time for the second gust to reach the turbine induces a different load on the tower of the turbine. Therefore, future work has to be devoted to a deeper understanding of the characteristics of events such as $T_c$ and $T_g$ on the atmospheric wind, their dependence on the parameters for their definitions and their relation to a purely turbulent flow. Additionally, evaluating the response of a wind turbine under different scenarios involving these structures might be beneficial, firstly as an insight into the source of unpredicted measured loads on an operating wind turbine or secondly, as improvements to current control practices.

Speaker: Daniela Moreno (ForWind, University of Oldenburg)

20221125_WomenPhysicsConf.pdf

5:30 PM Recent progress in the traceRadon project: Measuring outdoor Radon down to lowest activity concentrations

The alpha-decay chain of Rn-222 results to the highest dose contribution from natural radiation and by this exposure to the highest natural risk for developing lung cancer. Therefore, precise and quality assured measurements of radon are of great importance and EU member states are required to implement radon mitigation measures according to the European Council Directive 2013/59/EURATOM.
The outdoor Rn-222 activity concentration (typically in the range of 1 Bq/m³ to 100 Bq/m³) can be used to improve the identification of radon priority areas, where countermeasures are most needed. Despite an enlarging network of Rn-222 activity concentration measurements across Europe, traceability to SI at the outdoor level is still lacking.
The EMPIR project 19ENV01 traceRadon [1] addressed this issue and has developed several new radon emanation sources, to be used as calibration standards to calibrate reference instruments at the environmental level with uncertainties below 10 % for k = 1.
In this talk the radon emanation sources as well as their suitability for implementation as calibration standards will be presented.
[1]: This project 19ENV01 trace Radon has received funding from the EMPIR programme co-financed by the participating States and from the European Union's Horizon 2020 research and innovation programme.

Speaker: Dr Tanita Johanna Ballé (PTB)

Talk Tanita Balle.pdf

4:30 PM → 6:00 PM Physics Talks - Solid State Experiment

4:30 PM Highly-sensitive photodetachment spectroscopy in an MR-ToF device

The electron affinity (EA) reflects the released energy when an electron is attached to a neutral atom. An experimental determination of this quantity can serve as an important benchmark for atomic models describing electron-correlation effects [1]. A comprehensive understanding of these effects is also necessary for accurate calculations of the specific mass shift, which is required to extract nuclear charge radii from measurable total isotope shifts. By measuring small differences in the EA between different isotopes of the same chemical element, the isotope shifts of the EA, atomic models can be further constrained. However, isotope shifts in the EA have been experimentally determined only for very few stable nuclides so far, and only with modest precision. As an example, the isotope shift between the two stable chlorine (Cl) isotopes is more precisely predicted in theory [2] than experimentally measured [3].

Exploiting the low-energy version of the Multi Ion Reflection Apparatus for Collinear Laser Spectroscopy (MIRACLS) [4], we have initiated a high-precision measurement of the isotope shift in the electron affinity between stable Cl isotopes as well as the long-lived 36Cl isotope. This can be achieved by photodetachment threshold spectroscopy of negative Cl ions. By trapping ion bunches between the two electrostatic mirrors of MIRACLS’ multi-reflection time-of-flight (MR-ToF) device, the same ion bunch can be probed by the spectroscopy laser repeatedly. As a result, the photodetachment efficiency can be significantly increased in comparison to single-pass experiments. Thus, instead of conventionally used pulsed high-power lasers with a large linewidth, narrow-bandwidth continuous-wave (CW) lasers can be employed. Consequently, the measurement precision will be improved.

By confining the Cl- ions for a few 10,000s of revolutions in the MR-ToF device, neutralised atoms produced by photodetachment have been experimentally detected. For wavelengths only 3 nm above threshold, a CW laser power as low as 0.8 mW has been demonstrated to be sufficient to observe the process of photodetachment. The first experimental data indicates that the new method is 3 to 4 orders of magnitude more sensitive than conventional single-pass photodetachment experiments, see e.g. [1]. Thus, our novel measurement scheme paves the way for precision measurements of isotope shifts in the electron affinity between stable and ultimately radioactive Cl isotopes.

Due to its small floor space of just 2m x 1m, an MR-ToF apparatus can be easily installed at existing radioactive ion beam facilities. Combined with higher power lasers, the MR-ToF technique will hence allow measuring EAs and isotope shifts in the EA for various radioactive negative ions for the very first time.
The novel technique will be introduced and first experimental results will be presented.

Speaker: Franziska Maier (ISOLDE/CERN & University Greifswald/Germany)

Physikerinnentagung_negions.pdf

4:45 PM Highly crystalline $\text{In}_2\text{S}_3$ thin films epitaxially grown on sapphire substrates: A potential candidate for intermediate band solar cells

The Shockley Queisser limit of single junction solar cells can be overcome by introducing an intermediate band (IB) in wide band gap materials. Thus thermalization losses can be reduced [1]. Furthermore sub-bandgap photons can be absorped by valence band to IB and IB to conduction band transitions. According to theoretical calculations $\text{In}_2\text{S}_3$ hyper-doped with vanadium is a suitable candidate to realize such an IB solar cell [2].

We grew $\beta$-$\text{In}_2\text{S}_3$ thin films by physical co-evaporation of the elements on glass and on a-, c-, m-, and r-plane sapphire substrates. The deposition parameters were varied in a wide range to optimize the structural properties of the films. At appropriate deposition parameters (103)-orientation of $\beta$-phase $\text{In}_2\text{S}_3$ was enhanced. Highest crystallinity and smoothest surfaces could be realized for samples epitaxially grown on a-sapphire substrates.
Electrical characterization reveals a strong persistant photoconductivity. To investigate the photovoltaic response we fabricate $pn$-heterojunctions using amorphous $p$-type zinc-cobalt-oxide.

Further we grew $\text{In}_2\text{S}_3\text{:V}$ on sapphire substrates using a combinatorial approach to cover within a single deposition process a wide range of doping concentrations reaching from $1.1 \, \text{at.}\%$ to $11.4 \, \text{at.}\%$ vanadium.
For samples with doping concentrations above a critical concentration of $3.2 \, \text{at.}\%$ vanadium we find an unusual temperature dependence in mobility and charge carrier concentration, which might give evidence to the formation of an IB.

[1] Luque and Martí, Phys. Rev. Lett., 1997, 78, 5014.

[2] Palacios et al., Phys. Rev. Lett., 2008, 101, 046403.

Speaker: Ms Tanja Jawinski (Universität Leipzig, Felix-Bloch-Institut für Festkörperphysik)

5:00 PM Increasing System Efficiency and Functionality of Microelectronics: Multipurpose Group IV alloys

Microelectronics is a core of world technology, touching every aspect of modern life. After decades of downscaling being the technology driver, this has been replaced in recent years by energy efficiency and increased functionality. In particular, the integration with photonics by adding optical devices such as waveguides, modulators, detectors, and lasers, has been aimed for. Moreover, the explosion in data traffic calls for new computing paradigms and, combined with the demand to get access to data at almost any time and place, underlines the necessity for autonomous, grid-independent energy-efficient devices. Thermoelectric technology (TE) is one of the green technologies that have the potential to improve energy efficiency by improving system efficiency and recovering waste heat in multiple application fields, including data centres, mobile devices and various industrial production processes. Consequently, developing new high-performance thermoelectric materials is critical in expanding the range of large-scale thermoelectric applications.
In recent years, significant progress has been made in developing devices based on non-classical group IV alloys, particularly those containing Sn, such as GeSn. In contrast to the well-established Si and Ge-based materials, which have an indirect band gap, epitaxial GeSn layers exhibit a direct band alignment for Sn concentrations exceeding 8%. GeSn alloys with lower Sn concentration can be converted into a direct semiconductor by adding tensile strain. To this aim, it is paramount to correctly evaluate the effect of composition, strain, and the deposition process on the crystal quality of GeSn layers. For this purpose, Raman spectroscopy is an effective experimental technique to determine these properties, as it is a non-destructive, contactless, fast and spatially-resolved technique.
Moreover, GeSn alloys provide lower thermal conductivity than Ge or SiGe and better thermoelectric performance. We examined the thermal conductivity k of high-quality epitaxial GeSn layers with Sn content between 5% - 14% by Raman thermometry. In this method, the phonon energy is measured via Raman spectroscopy and is correlated to the heating induced by a laser beam. Subsequently, we determined the material's thermal conductivity by a semi-analytical model. The result is that k decreases from 56 W/m·K for pure Ge to 4 W/m·K for a Ge0.86Sn0.14 alloy. Measurements on SiGeSn show an even larger reduction down to 2 W/m·K.
Thus, GeSn is potentially suitable as the material basis for CMOS technology's monolithic integration of light emitters and thermoelectrics. These pave the way for thermoelectric devices fully compatible with CMOS technology toward a monolithic integration of electronics, photonics, and thermoelectric on the same chip.

Speaker: Mrs Agnieszka Anna Corley-Wiciak (IHP – Leibniz-Institut für innovative Mikroelektronik)

Corley-Wiciak_dpt.pptx

5:15 PM Electrical active defects caused by threading dislocations in Ge-rich GeSi heterostructures integrated on Si(001)

Ge-based devices have numerous applications in the field of photonics and optoelectronics. These include Ge as alternative channel material for high-performance MOSFETs [1], as near-infrared integrated light sources [2] and as active material for THz quantum cascade lasers (QCL) [3]. A CMOS-compatible fabrication requires the integration of Ge-based heterostructures on Si substrates. In this case, the lattice mismatch between Ge and Si (4%) leads to plastic relaxation and, therefore, the formation of threading dislocations (TDs). These extended defects can negatively influence the electrical properties of Ge-based optoelectronic devices.
Previous investigations of the electrical active defects caused by TDs in either n- or p-doped Ge(Si) films were carried out on devices with threading dislocation densities (TDDs) in the range of 107 to 1010 cm-2 including processing-induced defects [4,5,6]. By means of the recent reported reverse graded buffer technique using a benficial second interface in GeSi/Ge/Si heterostructures it has become possible to tune the TDD in Ge0.96Si0.04 layers in a wide range down to the low 106 cm-2 range by keeping thickness and degree of plastic deformation constant [7]. Since material physics as well as practical considerations such as fabrication cost can be expected to impose limits on a further reduction of the TDD, it is particularly important to obtain a quantitative understanding of the impact of TDs on device performance in the low density regime. This is at the focus of our investigation.
Here, we study undoped Ge-rich GeSi epitaxial layers featuring different values for the TDD ranging from 3∙106 to 2∙108 cm-2 grown on Si(001) using a Ge buffer. We present a comprehensive analysis of the influence of TDD on the vertical leakage currents in buried n+-p homojunctions. Here, the influence of TDs oriented parallel to the current path on device characteristics in as-grown Ge0.96Si0.04/Ge/Si heterostructures can be investigated without the introduction of processing-induced defects e.g. by implantation and annealing. The correlation of leakage currents and TDD shows a stronger than linear dependency and temperature dependent current-voltage (I-V) measurements reveals an electric field dependent carrier generation inside the diodes. In addition, capacitance-voltage (C-V) profiling of MOS capacitors fabricated on similar heterostructures gives information on TD related background doping in the studied Ge0.96Si0.04 layers. Associated DLTS measurements indicates an unintentional carrier concentration in the order of 3x1015 cm-3 above 175K and provide information on the included defect level characteristics.

[1] D.P. Brunco, B. De Jaeger, G. Eneman, J. Mitard, G. Hellings, A. Satta, V. Terzieva, L. Souriau, F.E. Leys, G. Pourtois, M. Houssa, G. Winderickx, E. Vrancken, S. Sioncke, K. Opsomer, G. Nicholas, M. Caymax, A. Stesmans, J. Van Steenbergen, P.W. Mertens, M. Meuris, M.M. Heyns, J. Electrochem. Soc. 155, H552 (2008)
[2] F.T. Armand Pilon, A. Lyasota, Y.-M. Niquet, V. Reboud, V. Calvo, N. Pauc, J. Widiez, C. Bonzon, J.M. Hartmann, A. Chelnokov, J. Faist, H. Sigg, Nat Commun. 10, 2724 (2019)
[3] T. Grange, D. Stark, G. Scalari, J. Faist, L. Persichetti, L. Di Gaspare, M. De Seta, M. Ortolani, D.J. Paul, G. Capellini, S. Birner, M. Virgilio, Appl. Phys. Lett. 114, 111102 (2019)
[4] E. Simoen, G. Eneman, G. Wang, L. Souriau, R. Loo, M. Caymax, C. Claeys, J. Electrochem. Soc. 157, R1 (2010)
[5] C. Claeys, E. Simoen, G. Eneman, K. Ni, A. Hikavyy, R. Loo, S. Gupta, C. Merckling, A. Alian, M. Caymax, ECS J. Solid State Sci. Technol. 5, P3149 (2016)
[6] E. Simoen, B. Hsu, G. Eneman, E. Rosseel, R. Loo, H. Arimura, N. Horiguchi, W. Wen, H. Nakashima, C. Claeys, A. Oliveira, P. Agopian, J. Martino, 34th Symposium on Microelectronics Technology and Devices (SBMicro), pp. 1-6 (2019)
[7] O. Skibitzki, M.H. Zoellner, F. Rovaris, M.A. Schubert, Y. Yamamoto, L. Persichetti, L. Di Gaspare, M. De Seta, R. Gatti, F. Montalenti, G. Capellini, Phys. Rev. Mat. 4, 103403 (2020)

Speaker: Henriette Tetzner (IHP GmbH)

Tetzner_25112022_1715.pdf

5:30 PM Substrate Influence on the Fano coupling of bright-dark modes in THz plasmonic n-doped Ge antennas

A complementary metal-oxide-semiconductor (CMOS) -compatible Germanium (Ge)/Silicon (Si) system holds the promise for compact, low-cost and simple connection to on-chip data storage, processing and/or communication systems based on mainstream Si-based microelectronics. At terahertz (THz) frequencies, the plasmonic properties of n-doped Ge enable localized surface plasmon resonances (LSPR) in bow-tie antennas that can be used for a state-of-the-art biosensing platform, and that in the future could integrate in microfluidics for lab-on-a-chip application.
In this work, we show the polarization-sensitive plasmonic resonance of highly doped Ge antennas and demonstrate an increase of the antenna quality factor (Q-factor) by Fano coupling of bright and dark modes. The dark mode is a traveling wave confined to the antenna substrate. The coupling of the bright mode (antenna resonance) to the dark mode is demonstrated as the substrate thickness is gradually changed. Moreover, we also report on the effect of different packing densities of antennas per mm2 and a direct dependency of the antenna density on the transmission is demonstrated.
Finally, Ge antennas on a highly-resistive silicon dioxide (SOI) substrate have no detrimental effect to bright-dark coupling and, with respect to antennas on Si substrate, show a Q-factor enhancement of ~21% for antennas without and of ~43% for antennas with Fano coupling. We believe these results could pave the way to a CMOS-integrated, low-cost biosensor platform.

Speaker: Mrs Elena Hardt (IHP - Leibniz Institut für innovative Mikroelektronik)

DPT_Elena_Hardt_25.11.2022.pptx

5:45 PM Design of Multilayer Stacks for Use as a Selective Emitter in a Thermophotovoltaic System

In a thermophotovoltaic (TPV) system, the photons radiated from a thermal emitter are converted into electrical power with the help of a photovoltaic cell. These systems are good for remote power generation, deep-sea applications, in space, and in utilizing solar heat, or heat wasted from other power generation plants, for example. A selective emitter is the best choice for the thermal emitter, as it restricts the emission of photons below the bandgap energy of the photovoltaic cell material. In this work, we simulate the emission of metal/insulator multilayers by calculating their absorption. If the absorption is known, the emission can be well predicted as stated by the Kirchhoff’s law where the amount of emission from a material is the same as the amount of absorption under equilibrium conditions. We thus studied the absorption spectra of Metal Insulator Metal (MIM) and Metal Insulator Metal Insulator Metal (MIMIM) multilayers made of six different metals each-TiN, Au, Ag, Al, W, Cu- and Silica or Hafnia as the insulators. It was shown that the broadness of the absorption peak could be varied by varying the metal, and by varying the thicknesses, the absorption intensity and position of the absorption peak can be tuned. The multilayers were tuned to the bandgap wavelength of Si, Ge and GaAs as photovoltaic cell references. An ideal selective emitter emits photons only around the bandgap wavelength of the photovoltaic cell, so the narrower the absorption peak, the better. In this regard, the best response was found for Ag, Au, Al and Cu as the metals in the multilayers. These absorption peaks were simulated using the transfer matrix method (TMM). In some of the simulations in this work, the absorption peak was greater than 85%, which is very well desired for this application.

Speaker: Ms Maria Masood (IHP microelectronics)

maria_masood.pdf

4:30 PM → 6:00 PM Workshop 2 (online only): "Self-marketing: Putting your best self forward": Evening

This workshop will take place exclusively online via zoom!

Trainer: Francesca Carlin

Self-marketing has become more and more important in this day and age, but there is very little guidance and resources on the best practices for academics. In addition, women in academia face challenges that their male-counterparts do not when it comes to marketing and visibility. This workshop aims to provide female academics with the tools and resources to enable them to market themselves effectively and with confidence.

Target groups: female PhD candidates, female postdocs

6:00 PM → 7:00 PM Commuting by bus: From Campus North to Campus South

7:00 PM → 9:00 PM Social program

• activities for leisure in Karlsruhe

Saturday, November 26

9:00 AM → 10:30 AM Physics Talks - Astroparticle Physics

9:00 AM Development of a Second-Level Trigger for the Autonomous Detection of Air-Shower Radio Emission

The Giant Radio Array for Neutrino Detection (GRAND) is a future observatory with unprecedented sensitivity to ultra-high energy (UHE) neutrinos. UHE neutrinos and cosmic rays (CR) induce extensive air showers (EAS) when they enter Earth's atmosphere. These EAS emit radio signals, which offer information on the mass, energy and arrival direction of the incoming CR.

GRAND is planned as a network of radio detection antennas, covering a total area of $200\,000\,$km$^2$, with one antenna per square kilometer. The antennas are designed to measure radio signals emitted by EAS in the range of $50-200\,$MHz. They will be deployed on mountain slopes, creating a structure that is optimized for detecting inclined air showers. Currently, the GRANDProto300 (GP300) experiment is being developed as a pathfinder for GRAND. It will consist of 300 detection units, distributed across an area of $200\,$km$^2$ at high altitude. GP300 is specifically designed for the measurement of very inclined air showers of zenith angles $>70^\circ$ at ultra-high energies. Its main goals are to demonstrate the GRAND detection principle and to offer insights on the scalability of the trigger.

Radio measurements are highly affected by anthropic signals, which can be several orders of magnitude more frequent than EAS. In order to reliably distinguish EAS events from noise, the NUTRIG project is developing an efficient and autonomous radio trigger, which will be verified with GP300. The first-level trigger describes the selection of an antenna signal, while the second-level trigger refines this selection according to information of all antennas triggered during the same event. This talk will cover the concept of the GRAND experiment and give an overview of the development of a second-level trigger for the autonomous detection of air shower radio emission.

Speaker: Jelena Petereit (KIT)

trigger_jpetereit.pdf

9:15 AM Improving the external trigger of AERA for extensive air showers at the Pierre Auger Observatory

The Pierre Auger Observatory is the world's largest detector for the detection of ultra high energy cosmic rays. It is designed as a hybrid detector with a Surface Detector (SD) and a Fluorescence Detector (FD) as its baseline components. The SD consists of 1600 stations, which cover an area of 3000 km$^2$. The entire field of the SD is overlooked by 27 telescopes, which are located at four FD buildings. The Auger Engineering Radio Array (AERA) consists of more than 150 antenna stations. It covers an area of about 17 km$^2$ and detects radio signals originating from air showers induced by the cosmic ray. The measurement of the air shower is used to reconstruct proparties of the primary cosmic ray particle.

The data read-out of AERA is triggered externally in particular by the SD. This results in many triggers for event that are not relevant for AERA as they are too far away. In addition, not all events of interest yield a trigger. To improve the external trigger, a new reconstruction method for determining the direction of an air shower on trigger level is presented. Based on this method different trigger-conditions are defined and tested. This results in a substantial improvement compared to the current AERA trigger.

Speaker: Ms Rukije Uzeiroska (Bergische Universität Wuppertal)

DPT_Presentation_Uzeiroska.pdf

9:30 AM Radio neutrino detection with RNO-G

Radio detection of neutrinos opens the possibility of measuring neutrinos with an energy above $10^{16}$ eV. The Radio Neutrino Observatory Greenland (RNO-G) is designed to measure the astrophysical neutrino flux at energies higher than IceCube and will enable investigations of fundamental physics at energies that are not attainable by particle accelerators. It uses an array of radio sensors and utilises the Askaryan effect in neutrino-induced cascades in ice.
Investigating the propagation of radio waves in ice is essential to properly evaluate data from radio neutrino observatories such as RNO-G. This includes understanding classically “forbidden” wave propagation, which can be empirically explained via computer simulations.
In this contribution, I will present RNO-G and its prospects, with a particular focus on the dedicated simulations of signal propagation.

Speaker: Karen Terveer (Friedrich-Alexander-Universität Erlangen-Nürnberg)

RNO-G_Presentation.pdf

9:45 AM MACS J1423.8+2404: gravitational lensing by a massive, relaxed cluster of galaxies at z = 0.54

Studying massive, relaxed galaxy clusters at high redshifts is key to understand the theoretical and numerical models of structure formation and evolution on cosmological time scales. An attempt is made to study the relaxed state of MACS J1423.8+2404 (z = 0.54, MACS J1423) using gravitational lensing. The MAssive Cluster Survey (MACS, Ebeling et al. 2001) is a compilation of very X-ray luminous 124 galaxy clusters at 0.3 < z < 0.7, including 12 clusters at z > 0.5 in the high redshift subsample (Ebeling et al. 2007). MACSJ 1423 is the most dynamically relaxed and the most massive cool-core cluster known at these redshifts. A model of MACS J1423 mass distribution is derived using strong-lensing constraints, i.e. multiple images in the cluster core which will be combined with weak-lensing measurements of gravitational shear on larger scales. I will present the methods used and the results of the derived projected mass of MACS J1423. I will also put my results in perspective of other lensing and multi-wavelength analyses (Limousin et al. 2010, Zitrin et al. 2011), to derive constraints on cluster evolution.

Speaker: Patel Nency (Durham University)

German conference of Women in Physics.pdf

10:00 AM Observing Dark Matter in Galaxy Clusters with Strong Lensing and MUSE Spectroscopy

Galaxy clusters are the most massive gravitationally-bound objects in the universe, and analysis of their structure can yield many fascinating answers and equally fascinating questions about the nature of the physics that holds them together. The presence of dark matter in galaxy clusters is one of the most pressing of these fascinating questions, and there are many techniques that are currently being used to study everything from the 'core-cusp' tension in cluster cores to the exact distribution of DM throughout the clusters. One of these techniques is called strong gravitational lensing, which effectively allows us to use massive objects -like galaxy clusters- as natural 'cosmic telescopes' to study highly magnified background sources. Lensing can also be used to study cluster substructure and model the dark matter distribution in these clusters. In this talk, I will discuss the use of lensing to model the mass distribution of several galaxy clusters observed with the Hubble Space Telescope (HST), which is used to identify lensed background sources, and with ground-based IFU spectroscopy from the MUSE instrument at the Very Large Telescope (VLT), which is used to measure 2-D galaxy kinematics. I will use these models to discuss how we can effectively constrain the shape of the density profiles in galaxy clusters with strong lensing, and I will additionally comment on what implications these profiles have for our overall understanding of the nature of dark matter.

Speaker: Catherine Cerny (Durham University)

CCernytalk - karlsruhe-1.pdf

10:15 AM Strong gravitational lensing: Nature’s cosmic telescope to reveal dark matter and the faintest galaxies in the universe

The strong gravitational lensing effect is a powerful technic to study both the deflector of light and the magnified sources behind it. In this talk, I will first review lens modelling approaches of galaxy clusters and present a state-of-the-art lensing mass model combining at the same time the Hubble Space Telescope, James Webb Space Telescope and large spectroscopic coverage. Such a combination allows us to have a very refined mass distribution (dark matter and baryons) of a cluster of galaxies. An analysis of a larger sample of strong lensing clusters reveals that the lensing strength has a stronger correlation with the slope of the density profile revealing the properties of the dark matter. I will also detail recent analyses revealing how the detailed study of the lensing effect distortion can discover a yet unobserved population of wandering supermassive black holes.
The second part of the talk will focus on the magnified universe behind the lens. Strong gravitational lensing offers unique opportunities that have no match in so-called regular fields, from the highly magnified galaxies seeing as they were 10 billion years ago about half the age of our universe, to the most distant galaxies at the dawn of the universe. Finally, I will discuss how the James Webb Space Telescope and future facilities such as the Rubin observatory or Euclid combined with strong lensing will revolutionise our view of the universe in the near future.

Speaker: Guillaume Mahler

GM-Women-inPhysics-26Nov2022_short.pdf

9:00 AM → 10:30 AM Physics Talks - Quantum Effects, Materials Physics

9:00 AM Quantum effects in black hole interiors

The strong cosmic censorship conjecture states that it is impossible to travel into spacetime regions where determinism breaks down, such as the innermost region of a charged or rotating black hole.
In this talk I present results on the influence of quantum effects on the strong cosmic censorship conjecture in charged black hole spacetimes. In addition, I discuss the (dis-)charge of charged black hole interiors by quantum effects, and give an outlook how similar results can be obtained for rotating black holes.

Speaker: Christiane Katharina Maria Klein (University Leipzig)

slides_0.pdf

9:15 AM Correlation measurements of the ground state of light

In analogy to the ground state of the quantum harmonic oscillator, the quantum ground state of light contains non-zero energy, the vacuum energy. On average, the ground state photon number is zero, but the existence of fluctuations in the electromagnetic field can be interpreted as the creation and destruction of virtual photons. Mathematically, the average field expectation value of the ground state vanishes while its variance is non-zero, corresponding to the field fluctuations. Direct measurements of the vacuum field by absorption are impossible because the energy extraction from the ground state is unphysical. However, the manifestation of the vacuum field in the Casimir effect, spontaneous emission, or the Lamb shift allows for indirect measurements of the vacuum state.

In this work, we present an approach using electro-optic sampling, which enables the direct measurement of the electric field fluctuations caused by the vacuum field. Electro-optic sampling (EOS) is based on the interaction of electric fields in the THz to the mid-infrared regime with a near-infrared probe signal in a non-linear crystal. The non-linear interaction of a probe pulse with the vacuum field in the crystal results in a detectable polarization change of the former. Consequently, the altered polarization offers information about the electric vacuum field amplitude. By performing this measurement using not only one but two separate probe beams having a certain time delay, the technique allows for the investigation of the temporal correlation function of the vacuum electric field. Additional spatial displacement of the probe beams enables us to access the spatial correlation function. Tuning both the temporal and spatial displacements allows for the characterization of the vacuum field at different space-time points, promoting the understanding of causal and non-causal connections of the vacuum electric field.

Speaker: Laura Sophie Gabriel (ETH Zurich, Institute of Quantum Electronics)

dpt_pdf_full.pdf

dpt.pptx

9:30 AM Non-Adiabatic Holonomic Quantum Computing in Integrated Quantum Optics

Quantum computing is among the most promising new research areas of modern physics. At its heart, it leverages non-classical effects in certain quantum systems to dramatically speed up computations and information processing. Addressing the need for highly stable quantum systems, a particularly promising paradigm for the design of quantum computers is holonomic quantum computing [1], i.e. the notion of implementing quantum gates as non-Abelian geometric phases. We present the experimental realization of non-adiabatic holonomic quantum gates and a quantum algorithm in integrated photonics.
The geometric phase accumulated by a propagating quantum system depends exclusively on its path through the underlying Hilbert space. As such, it stands in contrast to the dynamical phase, which records the passage of time. Due to their purely geometrical evolution, holonomies, i.e. multi-dimensional geometric phases [2], benefit from topological protection. In particular, the evolution described by non-adiabatic holonomies [3] is completely time- independent, making them especially suited for the design of holonomic quantum gates [4,5].
Quantum optics constitutes a particularly versatile platform for quantum information processing. It allows for the desired miniaturization and, due to the bosonic nature of photons, even the synthesis of holonomies of higher dimension as larger and more capable computational units [6,7]. Our demonstration consists of three waveguides in a planar geometry fabricated by femto-second laser direct inscription [8]. Exciting this structure with a single photon allows for the creation of a two-dimensional non-adiabatic holonomy.
As a proof of principle, we experimentally realize three prominent quantum gates: Pauli-X, Pauli-Z and Hadamard, as well as a small quantum algorithm: the quantum coin-flip game [9]. We find high fidelities, showcasing the high accuracy of our quantum optical realization of non-adiabatic holonomic quantum gates and gate sequences. Our findings pave the way towards universal holonomic quantum computing.

1. Zanardi, Rasetti, Phys. Lett. A 264, 94–99 (1999).
2. Wilczek, Zee, Phys. Rev. Lett. 52, 2111–2114 (1984).
3. Anandan, Phys. Lett. A 133, 171–175 (1988).
4. Sjöqvist, et al. New J. Phys. 14, 103035 (2012).
5. Abdumalikov, et al. Nature 496, 482–485 (2013).
6. Pinske, et al. Phys. Rev. A 101, (2020).
7. Neef, et al. Nature Phys, in press (2022).
8. Szameit et al. J. Phys. B At. Mol. Opt. Phys. 43, (2010).
9. Müller, Greinert, arXiv 2108.06271, (2021).

Speaker: Vera Neef (Institut für Physik, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany)

Holonomic-Gates_Physikerinnen_2_split.pdf

9:45 AM Numerical simulations and model development for metallurgical processes

Industrial production processes feature a range of fluid- or particle-based flows, converting primary or secondary raw materials and resources into highly refined products. Observations of flow details and measurements of flow patterns are particularly difficult in some industrial settings, where extreme process conditions like high temperatures and pressures, dust and chemical reactions prevent close scrutiny of the flow. Digitalization is a key ingredient for both the modelling and observability of such processes, since realistic digital models enable offline monitoring and exploration, and help to efficiently design and exploit suitable surveillance strategies. It is thus of high importance to advance the modelling and simulation of flow-based processes.
In this talk, I will give an overview of the different processes in iron- and steelmaking, and the modelling approaches being used in the description and analysis of these processes. Methods range from computational fluid dynamics, discrete element method or flowsheeting simulations to data-driven modelling employing machine learning and advanced data analytics. These approaches will be illustrated using the example of the Ruhrstahl-Heraeus treatment in steel plants, an essential process step in the production of ultra-clean steels.

Speaker: Dr Christine Gruber (K1-MET GmbH)

2022-11_DPT_Gruber_short.pdf

2022-11_DPT_Gruber_short.pptx

10:00 AM Direct spectroscopic identification of reactive metal-oxygen species

In transition metal-oxygen species, the way the oxygen atoms are bonded to the metal center is found to play a significant role in their reactivity, in view of different types of oxygen ligands and unusual oxidation states.$^{[1,2]}$ In particular, finding of compounds that present transition metals with unusual oxidation states or reactive oxygen species (superoxido, peroxido and oxygen centered radical) is of great scientific and technological interests, as they have key applications as oxidizing agents, catalysts, or reaction intermediates. $^{[1,2]}$

Here, we use X-ray absorption spectroscopy (XAS) at the oxygen K and metal L$_3$, M$_3$ or N$_3$ edges of [MO$_n$]$^+$ systems (M = transition metal, $n$ = integer) to identify the spectroscopic signatures of oxygen ligands and assign the oxidation state of the metal.$^{[3,4]}$ The [MO$_n$]$^+$ species in the gas phase are produced by argon sputtering of a metal target in the presence of oxygen. The cationic species are mass selected and accumulated in an ion trap. X-ray absorption spectra are then recorded in partial ion yield mode.$^{[5]}$ Our ion trap instrument is installed at the undulator beamline UE52-PGM at the Berlin synchrotron radiation facility BESSY II.

Reactive species, such as the superoxido, the ozonido, the oxygen centered radical and species containing high-valent transition metals, are analysed in stable conditions in the ground state inside the cryogenic ion trap. This method is here demonstrated to be an important tool to identify oxygen ligands, offering direct access to element specific electronic structures.

References
[1] Y. X. Zhao, et al., Phys. Chem. Chem. Phys. 13, 1925–1938 (2011).
[2] S. Riedel and M. Kaupp, Coord. Chem. Rev. 253, 606–624 (2009).
[3] M. da S. Santos, et al., Angew. Chem. Int. Ed., e202207688 (2022).
[4] M. G. Delcey, et al., Phys. Chem. Chem. Phys. 24, 3598–3610 (2022).
[5] K. Hirsch, et al., J. Phys. B: At., Mol. Opt. Phys. 42, 154029 (2009).

Speaker: Mayara da Silva Santos (Helmholtz-Zentrum Berlin für Materialien und Energie)

10:15 AM Disproportionation in gas-phase di-manganese oxide cluster revealed by X-ray absorption spectroscopy

Photosystem II, with its active center a CaMn$_4$O$_5$ cluster (OEC), is essential for photosynthesis and therefore O$_2$ production in nature [1]. The understanding of the electronic structure and properties of this complex plays an important role in designing artificial water-oxidizing complexes. During oxygen formation the OEC undergoes five distinct states called S$_0$-S$_4$ forming the Kok cycle. Despite detailed knowledge of S$_0$ through S$_3$ there is still a lack of information on S$_4$ due to challenges preparing OEC in this state [2]. However, two major competing models for S$_4$ have been proposed in the literature which involve distinctively different oxidation states namely Mn(IV) (and an oxygen radical) and Mn(V), respectively.
We performed X-ray absorption spectroscopy (XAS) in ion yield mode at the manganese L-edge and oxygen K-edge on a series of cryogenically cooled, mass-selected manganese oxide ions at 20 K.
Here, we report on Mn$_2$O$_3^+$ – a high-valent species with two μ-oxo bridges and a terminal oxo ligand, which forms a subunit of the OEC. Using XAS we find an unusual charge disproportionation in Mn$_2$O$_3^+$,where one manganese atom is in a high oxidation state, and stability of this complex in a H$_2$O ligand presence. The oxidation states were identified by by comparison to reference X Ray absorption spectra of other manganese compounds.

[1] N. Cox and et al. Electronic structure of the oxygen-evolving complex in Photosystem II prior to O–O bond formation. Science, 2014, 345, 804.
[2] J. Barber. A mechanism for water splitting and oxygen production in photosynthesis. Nature Plants, 2017, 3(4), 17041.

Speaker: Olesya Ablyasova (Helmholtz-Zentrum Berlin für Materialien und Energie)

WStalkAblyasova.pdf

9:00 AM → 10:30 AM Physics and Profession 2

9:00 AM Communicating science

Love it or hate it: talking about your science has become an integral part of every scientist’s life. But also non-scientists can do their part to get crucial messages across to media, funding agencies or the mysterious general public by supporting scientists, working out the messages, testing the strategy and generally asking the right questions and translating complicated stuff into everyday language. From a budding career in journalism the speaker found her way to the press offices of international labs and discovered the fascinating world of particle physics. Now a freelance science communicator, she will talk about her way into the business as well as present other paths into the world of science communication. She also has a few tips for those who want to try their hand at doing some communicating themselves.

Speaker: Barbara Warmbein (freelance)

Physikerinnen_Warmbein_DPT2022.pdf

9:30 AM My career as a particle physicist (so far)

I will summarize my career starting from school where I enjoyed math, then studying physics at a german university and then doing research at several major laboratories and universities world-wide. I spend about 16 years in the UK and the USA before I came back to Germany. Earlier this year I became the first ever female member of the directorial board of DESY, responsible for the area of particle physics. I will try to identify key turning points or events that shaped my career.

Speaker: Beate Heinemann

10:00 AM Aus der Wissenschaft zum Wissenschaftsverlag (From science to scientific publishing)

(English below)
Nach meinem Physikstudium an der Humboldt-Universität zu Berlin, meiner Promotion in experimenteller Elementarteilchenphysik an der University of Manchester und einem Postdoc an der Technischen Universität Dortmund bin ich von der aktiven Forschung zum Wissenschaftsverlag Springer Nature gewechselt. Seit 2018 bin ich dort beim Journal Nature Physics als Editorin für verschiedene Bereiche zuständig: von Teilchen- und Kernphysik über Plasma- und Astrophysik zu Kosmologie und Metrologie. Als Editorin wähle ich aus, welche wissenschaftlichen Artikel potenziell für Nature Physics in Frage kommen, organisiere den Peer-Review-Prozess und begleite die Artikel bis zur Veröffentlichung. Desweiteren schreibe und editiere ich Texte, um wissenschaftliche Ergebnisse einem breiteren Fachpublikum zugänglich zu machen. Da ich weiterhin auf dem aktuellen Stand der Forschung bleiben muss, besuche ich Konferenzen, besichtige Labore und tausche mich mit Wissenschaftler*innen aus. In meinem Vortrag werde ich einen Einblick in die Welt der Wissenschaftsjournale und die vielfältigen Aufgaben einer hauptberuflichen Editorin geben.

After my undergraduate studies at Humboldt University Berlin, I pursued a PhD in experimental elementary particle physics at the University of Manchester, which was followed by a postdoc at the Technical University in Dortmund. I decided to leave academia to join Springer Nature, a scientific publisher, in 2018. Since then, I have been an editor at Nature Physics, an interdisciplinary physics journal, where I am responsible for the areas of particle, nuclear, plasma and astrophysics as well as cosmology and metrology. As an editor, I select research papers according to their suitability for the journal, organize peer review and ideally see them through to publication. In addition, I write and edit texts to make scientific results more accessible to a broader physics audience. As I need to stay informed on recent developments in the areas I handle, I attend conferences, visit laboratories and connect with researchers. In this talk, I will give an introduction into the world of scientific journals and into the various tasks of a professional editor.

Speaker: Dr Stefanie Reichert

Reichert_Physikerinnentagung_26112022.pdf

9:00 AM → 10:30 AM Workshop 3 (offline only): "Weg in die Professur": Morning

Trainer: Dr. Ulrike Preißler

Das Berufsziel "Professur" kann auf unterschiedlichen Wegen erreicht werden. Im Workshop sollen typische Karrierewege zur Voll-Professur (W2/W3) beleuchtet werden, die über eine Habilitation, habilitationsäquivalente Leistungen, Forschungsgruppenleitung oder eine Juniorprofessur beschritten werden können. Es sollen im Workshop u.a.

diese Fragen beantwortet werden: Wie sehen die Einstellungsvoraussetzungen für eine Professur aus, welche Leistungen in Forschung und Lehre werden erwartet und welche Kenntnisse und Fähigkeiten sollten die Professurbewerberinnen innehaben? Wie erreicht man eine hohe Sichtbarkeit in der wissenschaftlichen Szene und wie sieht es - gerade in der Qualifizierungsphase und als junge Professorin - mit der Vereinbarkeit von Beruf und Familie aus?"

Target groups: female PhD candidates, female postdocs

9:00 AM → 10:30 AM Workshop 4 (online only): "Becoming appointable: the path to a professorship": Morning

This workshop will take place exclusively online via zoom!

Trainer: Dr. Margarete Hubrath

At the end of their PhD studies or during their postdoc years many scientists are faced with the vital question of which way to go in the future: What are my professional goals and career aspirations? Do I see my future path in academia? Do I have the expertise and competencies required for a professorship in my field? Finding individual answers to these questions can be regarded as a crucial prerequisite for happiness and satisfaction with one’s professional development. The online workshop has two objectives: on the one hand, participants receive differentiated information about possible career paths towards a professorship with their conditions and requirements. On the other hand, participants will become acquainted with key elements and methods of career planning. Following the concept of triadic career counselling professional achievements as well as more personal aspects like individual preferences, motivational factors and the situation in one’s special field will be taken into account.

Target groups: female PhD candidates, female postdocs

10:30 AM → 11:00 AM Coffee break

11:00 AM → 12:30 PM Physics Talks - Astroparticle and Experimental Particle Physics

11:00 AM Search for the rare decay $\Omega_{b}^{-} \to \Omega^{-}\mu^{-}\mu^{+}$ at the LHCb experiment

Rare decays of heavy-quark hadrons provide a powerful way to probe indirectly for presence of phenomena beyond the Standard Model of particle physics.
At the LHCb experiment several ${b\to s\ell\ell}$ transitions, such as the rare decays $B\to K\ell\ell$ or ${B\to K^{*}\ell\ell}$, have been studied. They show tensions towards the Standard Model predictions in several observables, such as lepton universality ratios ($R_{K}$, $R_{K^{*}}$) or angular observables. So far most of the measurements have been focused on mesons and the $\Lambda_{b}$ baryon. To improve the understanding of the anomalies and widen the available knowledge, it is crucial to study ${b\to s\ell\ell}$ transitions for other weakly decaying baryons as well.

Therefore, the primary aim of the presented analysis is to observe the decay ${\Omega_{b}^{-} \to \Omega^{-}\mu^{-}\mu^{+}}$. If successful, the branching ratio relative to the decay ${\Omega_{b}^{-} \to \Omega^{-} J/\Psi(\to\mu^{-}\mu^{+})}$ will be measured.

The used data set corresponds to an integrated luminosity of ${9\:\mathrm{fb}^{-1}}$, which has been collected with the LHCb experiment from 2011 to 2018. In this talk the current status of the analysis is presented.

Speaker: Janina Nicolini (TU Dortmund University/ Université Paris-Saclay)

PhysikerinnenTagung_JNicolini.pdf

11:15 AM Top quark measurements at the Large Hadron Collider

The Standard Model (SM) of particle physics is our best description of the fundamental forces and particles in the universe, though there are many observed effects that it does not explain. To explain such phenomena, we require new physics. The top quark, as the heaviest known fundamental particle, offers a window into potential new physics. This talk focuses on measurements of rare top quark processes involving other heavy particles using data collected by the ATLAS detector during proton-proton collisions at the Large Hadron Collider. Such measurements are stringent tests of the SM.

Speaker: Ms Harriet Watson (University of Glasgow)

HWatson_DPT2022_TopPhysicsLHC_26112022.pdf

11:30 AM Multiboson measurements at CMS

Measurements of the multiboson production cross sections at the LHC constitute stringent tests of the electroweak sector of the standard model and provide a model-independent means to search for new physics at the TeV scale. These measurements reached a high level of precision with LHC run 1 and run 2 data taking periods. In this presentation, the latest results of diboson (WW, WZ, ZZ, W/Zγ), triboson (WWW, WWZ, WZZ, ZZZ), and rare production mechanisms (electroweak and photon-induced) from the CMS experiment will be shown. Results include total and fiducial cross sections, as well as normalized differential cross sections in the fiducial region. These are compared to the most accurate theoretical predictions to the date.

Speaker: Ankita Mehta (University of Hamburg)

multiboson_measurements_dpt_AM.pdf

11:45 AM Search for Dark Matter with the XENONnT experiment

The XENON collaboration is dedicated to understand the nature of dark matter. The XENONnT experiment, located at Laboratori Nazionali del Gran Sasso (LNGS) in italy, is aiming for a direct detection of weakly interacting massive particles (WIMPs) with a ton-scale dual-phase xenon time projection chamber. XENONnT has completed its first science run and is now taking data for the second science run at an unprecedented low background level.
The talk will present the goals and the status of the XENONnT experiment as well as its first results, e.g. the probing the excess seen by its predecessor XENON1T at low energy energetic recoils.

This work is supported by BMBF under contract 05A20PM1 and by DFG within the Research Training Group GRK-2149.

Speaker: Johanna Jakob

JJakob_Dark_matter_XENONnT.pdf

12:00 PM [Meta]data curation in astroparticle physics on KCDC usecase

Experimental research in astroparticle physics is performed using large scale setups and involves accumulation of big data amounts in long-term time scales. A remarkable example of such experiment is KASCADE (KArlsruhe Shower Core and Array DEtector), which took place from 1996 until 2013 at the location which is now KIT university Campus Nord. Fulfillment of the inverstigation goals at every stage of the research life cycle required employment of cutting edge technologies from that time period and effective data management approaches. Practices developed by the KASCADE IT support team represent an important example of data curation for the astroparticle physics projects. Nowadays, these solutions are employed at the KCDC (KASCADE Cosmic-ray Data Center) and support both analysis work done by professional researchers and outreach activities for a broader public.
Study of data curation approaches, employed in well-known data centers, such as KCDC, is of big value for modern actively developing projects, such as PUNCH4NFDI (Particles, Universe, NuClei and Hadrons for Nationale Forschungs-Daten Infrastruktur). Collection and analysis of multiple use cases aids to find both common grounds and diversities within established practices for data and metadata handling, which are as relevant for astroparticle physics as for other closely related research fields (particle physics, astronomy to name a few).
In this talk we present an overview of the data and metadata features in KCDC as well as data life cycles and pipelines employed in the system, data storage architecture, software and technologies used for development as well as the functionality of the system.
This work was [in part] supported by DFG fund „NFDI 39/1“ for the PUNCH4NFDI consortium.

Speaker: Victoria Tokareva (KIT)

DPT_26Now2022_Tokareva_Metadata_KCDC.pdf

11:00 AM → 12:30 PM Physics Talks - Biophysics, Medical Physics

11:00 AM Dose-efficient X-ray phase contrast imaging by Bragg magnifier optics

Synchrotron-based X-ray imaging of biological samples is often hindered by the radiation dose deployed in the sample, in particular for in vivo imaging and at μm-resolution. Many efforts have been made to reduce the dose, e.g., by propagation-based phase contrast imaging at high photon energies (~30 keV) [1, 2]. However, the detection efficiency of indirectly converting, scintillator-based detector systems, usually employed for such measurements, drops significantly at these energies, especially for thin scintillators that are required for high resolution.
To overcome this bottleneck, we developed a so-called Bragg Magnifier (BM) system optimized for 29-31 keV. By Bragg diffraction from asymmetrically cut silicon single crystals, a 2D magnification of the X-ray beam profile up to a factor 150 is possible, with a sample placed upstream or downstream of the system realizing a microscope (BMM) or beam conditioner (BMC), respectively. In BMM mode and combined with a highly efficient large-area detector, e.g. a high-Z single photon counting detector, an overall detection efficiency of over 90% can be achieved at ~1 μm effective spatial resolution. In BMC mode, a large beam and thus a cm-sized field of view is achievable even at short beamlines and with the intrinsically small beams of 3rd and 4th generation synchrotrons. Here, we present first experimental results, demonstrating the theoretically predicted high detection efficiency at ~1 μm spatial resolution, as well as an exemplary application of the system to dose-efficient in vivo X-ray imaging of parasitoid wasps.

Speaker: Rebecca Spiecker (Karlsruhe Institute of Technology, Laboratory for Applications of Synchrotron Radiation)

RebeccaSpiecker.pdf

11:15 AM BK-channel as a fast and precise Ca2+ sensor: application to PMCA pump strength measurements

$Ca^{2+}$ diffusion within cells and penetration of $Ca^{2+}$ through their membrane engages a wide field of theoretical and experimental research. Therefore, the monitoring of rapid changes of the $Ca^{2+}$ concentration beneath the cell membrane is of great interest. Here, we make use of BK-type $Ca^{2+}$-activated $K^+$ channels to determine the $Ca^{2+}$ activity of PMCA, which transport $Ca^{2+}$ ions out of cells. Due to their large conductance and their particular gating kinetics the BK channels may be used as fast and reliable sensors for intracellular $Ca^{2+}$ - concentration beneath the plasma membrane. Experimentally we monitor the PMCA-mediated $Ca^{2+}$ clearance (or transport) by the decay of BK-currents following their activation by a short (0.8 ms) period of $Ca^{2+}$ -influx through Cav2.2 channels. To relate the experimentally observed temporal evolution of the $K^+$ current to the underlying temporal evolution of the $Ca^{2+}$ concentration we implement a theoretical model for the $Ca^{2+}$-dependence of the BK-current and of the PMCA pump strength. Next to the transport in and out of a cell and the diffusion of $Ca^{2+}$ ions within the cell, we expand our model by the reaction of the $Ca^{2+}$ concentration with a buffer solution, as well defined EGTA concentration is present in all experimental measurements. We fit the PMCA pump strength by the best match of the predicted time course of the $K^+$ current with the experimental data. It turns out that this pump strength is at least 2 orders of magnitude larger than what has been assumed so far.

Speaker: Barbara Schmidt (Saarland University)

DPT_Barbara_Schmidt.pdf

11:30 AM How diamond sensors can help to understand the magnetic sense of animals

The ability of many animal species to orient themselves during long distance journeys around the globe is a fascinating topic. Althoughit has been known for decades that many of these species can sense the geomagnetic field and to use it as a navigation aid, the underlying sensory mechanisms are still poorly understood. One hypothesis is that magnetic particles might be part of such a sensor. Magnetic stray fields of such particles can be detected with the help of Optically Detected Magnetic Resonance (ODMR). In this method, fluorescent signals of defects in a diamond are readout while sweeping microwaves tuned to frequencies close to expected resonances. This allows us to detect very small magnetic fields at room temperature inside tissue sections.

Speaker: Dr Franziska Curdt (Universität Oldenburg)

11:45 AM Multi-method characterization of bone to find correlations between biological and material properties

The complex hierarchical structure of bone undergoes a lifelong remodeling process, where it adapts to mechanical needs. Hereby, bone resorption by osteoclasts and bone formation by osteoblasts have to be balanced to sustain a healthy and stable organ. Osteocytes orchestrate this interplay by sensing mechanical strains and translating them into biochemical signals.
The osteocytes are located in lacunae and are connected to one another and other bone cells through small channels, the canaliculi. Lacunae and canaliculi form a network (LCN) that is able to transport ions and enables cell-to-cell communication. Osteocytes might also contribute to mineral homeostasis by direct interactions with the surrounding matrix. If the LCN is acting as a transport system, this should be reflected in the mineralization pattern. Our hypothesis is that osteocytes are actively changing their material environment. Characteristical methods of solid state and surface physics are used to achieve the aim of detecting traces of this interaction between osteocytes and the extracellular matrix.

The measurement strategy included routines that make it possible to analyze the organization of the LCN and the material components (i.e., the organic collagen matrix and the mineral particles) in the same bone volumes and compare the spatial distribution of different data sets. The three-dimensional network architecture of the LCN is visualized by confocal laser scanning microscopy after Rhodamine staining and is then quantified. The calcium content is determined via quantitative backscattered electron imaging, while small and wide-angle X-ray scattering are employed to determine the thickness and length of local mineral particles.

In each of the three model systems, this study found that changes in the LCN architecture spatially correlated with bone matrix material parameters. While not knowing the exact mechanism, these results provide indications that osteocytes can actively manipulate a mineral reservoir located around the canaliculi to make a quickly accessible contribution to mineral homeostasis. However, this interaction might be an interplay between osteocytes and extra-cellular matrix, since the bone matrix contains biochemical signaling molecules that can change osteocyte behavior. Bone (re)modeling can therefore not only be understood as a method for removing defects or adapting to external mechanical stimuli, but also for increasing the efficiency of possible osteocyte-mineral interactions during bone homeostasis. With these findings, it seems reasonable to consider osteocytes as a target for drug development related to bone diseases that cause changes in bone composition and mechanical properties.

Speaker: Ms Victoria Schemenz (Department for Operative, Preventive and Pediatric Dentistry CC3 - Centrum für Zahn-, Mund- und Kieferheilkunde Charité - Universitätsmedizin Berlin)

22-11-26-physikerinnentagung-victoriaSchemenz.pdf

11:00 AM → 12:40 PM Physics and Profession 3

11:00 AM Microchips for Megatrends – Work where tomorrow is made

In this talk, I would like to outline my daily tasks at my job at ZEISS Semiconductor Manufacturing Technology and my academic path to arriving here. I completed degrees in physics in several countries: Bachelor’s degree from the University of Luxembourg, Master’s degree from Joseph Fourier University in Grenoble and a PhD from the Aix-Marseille University. Since finishing my PhD four years ago, I have been working at ZEISS Semiconductor Manufacturing Technology as a research assistant. My day-to-day work cannot be described in a single sentence as it varies and is challenging. It extends from preparing two 40T vacuum chambers for our high-end processes, through to testing our processes on new materials to project planning for the next fiscal year. Slowly but surely, my colleagues and I are contributing every day to creating even small and faster semiconductors – until we reach the limits of Moore’s law?

Speaker: Miriam Carlberg (Carl Zeiss AG)

221126_Zeiss_presentation_MCarlberg.pdf

11:20 AM Introduction to Infineon and opportunities for female physicists

In this talk, I would like to give you insights into my job at Infineon Technologies and into my career and life path. I completed my PhD with a focus on semiconductor physics in 2019 at the Technical University of Munich. After finishing my degree, I participated in the MBA program of the Collège des Ingénieurs and I am currently working as a project manager for research and development excellence at Infineon since December 2020.
My day-to-day job involves creating and improving methods and processes that help to make R&D projects run more efficiently, for example by using data to create additional insights. For this, I work together with colleagues from many different departments, in different functions and across organizational levels. My physics degree allows me to do my job because it enables a fundamental understanding of the technologies and products Infineon is offering, of how to create and handle data, and it has taught me how to analyze and solve complex questions in a systematic way.

Speaker: Hannah Schamoni (Infineon Technologies AG, Am Campeon 1-15, 85579 Neubiberg)

Physikerinnentagung2022_Vortrag-Schamoni_Infineon.pdf

11:40 AM Investigation of structural and dynamical properties of thermoresponsive polymers

With my talk, I would like to present my work at the Forschungszentrum Jülich and some information about my career path. I have done my Physics studies in Italy, at the University of Perugia (where I did my Bsc and PhD) and of Rome "La Sapienza" (where I did my Msc). During these years, I’ve been focusing on structural and dynamical properties of thermoresponsive polymers. In February 2022 I have started a postdoc at the Jülich Centre for Neutron Scattering (JCNS) at the FZJ, where I have the possibility to deepen my knowledge of polymer-based materials, from sample synthesis to data treatment and analysis.

Speaker: Benedetta Petra Rosi (Forschungszentrum Jülich)

Physikerinnentagung2022.pdf

12:00 PM Analytical. Quantitative. Tech – from physics to d-fine

In this talk I would like to tell you about my career at d-fine GmbH. After finishing my PhD in Physics at the Erlangen Centre for Astroparticle Physics at the University of Erlangen, I started working at d-fine as a consultant. I worked on many different projects with different team sizes (1-40) and different lengths (2 weeks to several years). Now I am a manager and my day-to-day job involves leading projects and leading people. At d-fine I have the opportunity to work with extraordinary people, who have excellent quantitative, analytical and technical skills and always support each other. My physics degree enables me to solve complex problems, which is something I still need to do on a daily basis.

Speaker: Constanze Jahn (d-fine GmbH)

Career_d-fine_DPT112022.pdf

12:20 PM Exploring and shaping future technology at Bosch Research as a physicist

In this talk, Elisabeth and Janine, two physicists from Bosch Research would like to share their different career paths from academia to industry as well as their passion about cutting-edge research in future fields like quantum sensing, machine learning or fuel cell systems.

Janine Riedrich-Moeller received her franco-german Master degree in physics from the Saarland University, Germany and the Université de Henri-Poincaré Nancy, France. After completing her PhD studies in the quantum optics group at the Saarland University, she joined the corporate research division of the Robert Bosch GmbH in Renningen, Germany, in 2015. In the domain of microsystems and quantum technology, she concentrates on the realization of quantum sensors for automotive and consumer applications.

Elisabeth Schwarz completed her physics degree (M.Sc.) at Technische Universität Dresden in 2019 with a Master thesis in the field of organic electronics. After this, she joined Bosch Research in Renningen as a doctoral student. In her PhD studies in mechanical engineering with the TU Ilmenau production technology group, she combines machine learning and physical simulations for improved quality prediction in welding processes. From October 2022 on, Elisabeth will work as a research engineer in the cyber-physical systems department of the Bosch Solid Oxide Fuel Cell (SOFC) division.

Speakers: Mrs Elisabeth Schwarz (Bosch Research, Robert Bosch GmbH), Mrs Janine Riedrich-Moeller (Bosch Research, Robert Bosch GmbH)

221126_Physikerinnentagung.pdf

221126_Physikerinnentagung.pptx

11:00 AM → 1:00 PM Schülerinnenprogramm: Programmieren für SchülerInnen

Programmieren für Schülerinnen
“Programmieren für Schülerinnen” richtet sich an Schülerinnen die keine Vorkenntnisse zum Thema Programmieren haben aber motiviert sind Neues zu lernen und einen Einblick in dieses spannende Feld bekommen möchten.
Das Ziel ist es, den Schülerinnen eine grundlegende Idee zu vermitteln was Programmieren ist und wie es funktioniert. In dem Workshop wird die Programmiersprache Python verwendet. Diese ist sehr einfach zu lernen und wird in der Physik meistens verwendet.
Der Workshop wird im Computerraum der Fakultät für Physik stattfinden und von Studierenden der Physik betreut werden.

11:00 AM → 12:30 PM Workshop 3 (offline only): "Weg in die Professur": Noon

Trainer: Dr. Ulrike Preißler

Das Berufsziel "Professur" kann auf unterschiedlichen Wegen erreicht werden. Im Workshop sollen typische Karrierewege zur Voll-Professur (W2/W3) beleuchtet werden, die über eine Habilitation, habilitationsäquivalente Leistungen, Forschungsgruppenleitung oder eine Juniorprofessur beschritten werden können. Es sollen im Workshop u.a.

diese Fragen beantwortet werden: Wie sehen die Einstellungsvoraussetzungen für eine Professur aus, welche Leistungen in Forschung und Lehre werden erwartet und welche Kenntnisse und Fähigkeiten sollten die Professurbewerberinnen innehaben? Wie erreicht man eine hohe Sichtbarkeit in der wissenschaftlichen Szene und wie sieht es - gerade in der Qualifizierungsphase und als junge Professorin - mit der Vereinbarkeit von Beruf und Familie aus?"

Target groups: female PhD candidates, female postdocs

11:00 AM → 12:30 PM Workshop 4 (online only): "Becoming appointable: the path to a professorship": Noon

This workshop will take place exclusively online via zoom!

Trainer: Dr. Margarete Hubrath

At the end of their PhD studies or during their postdoc years many scientists are faced with the vital question of which way to go in the future: What are my professional goals and career aspirations? Do I see my future path in academia? Do I have the expertise and competencies required for a professorship in my field? Finding individual answers to these questions can be regarded as a crucial prerequisite for happiness and satisfaction with one’s professional development. The online workshop has two objectives: on the one hand, participants receive differentiated information about possible career paths towards a professorship with their conditions and requirements. On the other hand, participants will become acquainted with key elements and methods of career planning. Following the concept of triadic career counselling professional achievements as well as more personal aspects like individual preferences, motivational factors and the situation in one’s special field will be taken into account.

Target groups: female PhD candidates, female postdocs

12:30 PM → 2:00 PM Lunch break

12:45 PM → 1:45 PM AKC Meeting

2:00 PM → 2:45 PM Keynote Physics Talks 3: Future Colliders - Dr. Edda Gschwendtner, CERN

Keynote Physics Talks 3

2:00 PM Future Colliders

The construction of ever larger and costlier accelerator facilities has its limits, and new technologies will be needed to push the energy frontier. Plasma wakefield acceleration is a rapidly developing and promising field which provides acceleration gradients a factor 10 to 1000 larger than in conventional radio-frequency metallic cavities used in current accelerators.
This presentation introduces the plasma wakefield acceleration technology, shows the technological challenges, gives an overview of the state of the art and shows promising results of the advanced proton driven plasma wakefield experiment, AWAKE, at CERN.

Speaker: Edda Gschwendtner (CERN)

2:00 PM → 2:45 PM Keynote Physics Talks 4: Biophysics - Prof. Elisabeth Fischer-Friedrich, Hertha-Sponer Prizewinner 2022, TU Dresden

Keynote

2:00 PM Deciphering a smart material – a new method to measure actin cortex mechanics and mechanosensitivity

The actin cortex is a thin polymer network beneath the plasma membrane in animal cells. It acts as a mechanical shield of the cell and as a major regulator of cell shape and cell migration. The actin cortex is a complex material with time-dependent viscoelastic mechanical properties. It is further subject to a self-generated active contractile stress and to constituent turnover. I will discuss our measurement results on frequency-dependent cortical viscoelasticity measured by atomic force microscopy. In addition, I will discuss how mechanosensitivity of molecular bonds can affect molecular composition of the cortex and how this mechanosensitivity can be quantified in live cells.

Speaker: Mrs Elisabeth Fischer-Friedrich (Excellence Cluster Physics of Life, TU Dresden)

2:00 PM → 3:00 PM Vortrag für Schülerinnen: Geophysik - Annika Maier, KIT

Geophysik Vortrag von Annika Maier

Was ist eigentlich Geophysik? – Genau diese Frage bestimmt das Thema dieses Vortrages. Als Randdisziplin der Physik und der Geowissenschaften, untersucht die Geophysik die Erde mittels physikalischer Methoden. Dazu gehören die Erforschung des Aufbaus und der Struktur der Erde, dynamische Prozesse im Erdinneren, die Untersuchung und Einschätzung von Naturgefahren, Geothermie, Untergrunduntersuchungen und Rohstoffexploration. Neben einem Überblick über die Geophysik wird auch auf das Studium am KIT, sowie die anschließend vielfältigen Berufsmöglichkeiten eingegangen.

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2:45 PM → 3:30 PM Keynote Physics Talks 3: Nonlinear Optics - Prof. Cornelia Denz, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin

Keynote Physics Talks 3

2:45 PM Graphene by light – how nonlinear optics creates artificial topological matter

Graphene with its hexagonal band structure of the energy spectrum has been celebrated in the past years as an ultrathin wonder material due to its intriguing features. Thus, it is a long-standing dream of solid-state physics to vary this lattice structure beyond graphene in order to extend the features of two-dimensional (2d) materials for example to topological insulation.

While condensed matter systems are difficult to adapt, optically- created artificial dielectric photonic matter represent an ideal testbed for these 2d materials. This has led to the field of topological photonics, an emerging field in which geometrical and topological concepts are implemented to mold the flow of light.

In our contribution, we introduce into this field of nonlinear optics, explaining how to fabricate those 2d photonic materials and demonstrate new 2d photonic materials as twisted bilayer graphene or photonic borophene, the optical equivalent of the new rising star of solid-state physics. We also showcase fascinating topological effects including nonlinear light localization in higher-order topologies.

Speaker: Prof. Cornelia Denz (University of Muenster)

2:45 PM → 3:30 PM Keynote Physics Talks 4: Theory (Complex Fluids and Soft Matter) - Prof. Annette Zippelius, Max Planck Medaille Prizewinner 2022, University of Göttingen

Keynote

2:45 PM Disordered Solids

We discuss a phase of matter which is charcterized by random localization of the atoms or molecules and a finite restoring force for static shear deformations. The following questions will be addressed: What is an appropriate order parameter for the amorphous solid state? How can we characterize its random structure? How do long range elastic correlations develop at the glass transition? These questions will be discussed by means of a statistical mechanical theory of disordered system as well as generalised hydrodynamics.

Speaker: Prof. Annette Zippelius (Georg-August Universität Göttingen)

3:30 PM → 4:00 PM Coffee break

4:00 PM → 6:00 PM Market Place

4:00 PM → 6:00 PM Poster session

4:00 PM 2D spectroscopy for the Detection of Electron-Phonon Coupling in Perovskites and Cuperates

The study of coupling between electron-phonon is of fundamental importance to understand Perovskites with interesting photoelectric properties, to address the problem related to the transport properties of materials and to contribute to the debate on the role of electron-phonon coupling in high critical temperature superconductors. Here we present a new approach to detecting the strength of electron-phonon coupling, which is complementary to the usual resonant inelastic x-ray scattering (RIXS), Angle-Resolved Photoemission (ARPES) and emission line broadening with temperature methods for the detection of electron-phonon coupling strength. We suggest a method which combines 2D pump-probe methods and Two phonon absorption in a single experiment to measure the electronic and phonic band gap of the system as well as the e-p coupling strength of Frohlich Hamiltonian. Our calculation is supported by the experimental results on the lead halide perovskites.

Speaker: Mr Vishal Kumar Sharma (Goethe University, Frankfurt am Main )

4:00 PM A Graphical Formalism for Entanglement Purification

Hypergraph states form an interesting family of multi-qubit
quantum states which are useful for quantum error correction,
non-locality and measurement-based quantum computing. They are
a generalisation of graph and cluster states. The states can be
represented by hypergraphs, where the vertices and hyperedges
represent qubits and entangling gates, respectively.

For quantum information processing, one needs high-fidelity
entangled states, but in practice most states are noisy.
Purification protocols address this problem and provide a
method to transform a certain number of copies of a noisy
state into single high-fidelity state. There exists a purification
protocol for hypergraph states [1]. In my talk, I will first
reformulate the purification protocol in a graphical manner,
which makes it intuitively understandable. Based on this, I
will propose systematic extensions, which naturally arise from
the graphical formalism.

[1] T. Carle et al., Phys. Rev. A 87, 012328 (2013)

Speaker: Lina Vandré (Uni Siegen)

4:00 PM A Look at General Neutrino Interactions with KATRIN Data

The KATRIN experiment aims to measure the neutrino mass by precision spectroscopy of tritium β-decay. Recently, KATRIN has improved the upper bound on the effective electron-neutrino mass to 0.8 eV/c² at 90% confidence level [1] and is continuing to take data for a target sensitivity of 0.2 eV/c².
In addition to the search for the neutrino mass, the ultra-precise measurement of the β-spectrum can be used to probe physics beyond the Standard Model. In particular, general neutrino interactions (GNI) [2] can be investigated through a search for potential shape variations of the β-spectrum. For this purpose, all theoretically allowed interaction terms for neutrinos are combined in one effective field theory. This enables a model-independent description of novel interactions, which could provide small contributions to the weak interaction. Such potential modifications can then be identified in the KATRIN β-spectrum by means of energy-dependent contributions to the rate.

The poster will introduce the theoretical background of the general neutrino interactions, give an overview of the analysis method and present first sensitivity studies.

[1] The KATRIN Collaboration. Direct neutrino-mass measurement with sub-electronvolt sensitivity. Nature Physics 18, 160–166, 2022.
[2] Ingolf Bischer and Werner Rodejohann. General neutrino interactions from an effective
field theory perspective. Nuclear Physics B, 947, 2019.

Speaker: Caroline Fengler

4:00 PM A New Beam Halo Veto Detector for the MAGIX Experiment

The MESA accelerator will host the MAGIX experiment, which is based on the
scattering of an electron beam on a gas jet target. This enables the scattering on gases like hydrogen without scattering on any other materials before and after the scattering process. The gas jet target is realized by using a nozzle to inject the gas into the scattering chamber as well as a funnel-shaped structure called the catcher, into which the gas streams behind the interaction zone.
So-called beam halo electrons can occur in the accelerator. These do not move exactly along the beam axis and can increase background by interacting with the catcher and the nozzle. To reject these scattering reactions, the beam halo veto detector was implemented. This detector is positioned upstream of the gas jet target inside the scattering chamber. It allows the detection of single electrons by using a scintillator, a lightguide and a photomultiplier tube. Therefore, covering the front of the nozzle and the catcher with this detector allows suppressing the described background.

Speaker: Judith Schlaadt

4:00 PM APPLICATION/TECHNOLOGY-INSPIRED DESIGN OF QUANTUM DOT MODELS FOR ELECTRON DYNAMICS SIMULATIONS

Quantum dots (QDs) are semiconducting nanoparticles important due to their size-tunable
excitation energy and other optical properties. Self-assembled (SA) QDs are one of the most
promising building blocks for future quantum information processing, as they can host optical,
electronic, or spin qubit states with a decent lifetime1,2.
Qubit switching itself is a dynamical process which is, e.g., driven by external electromagnetic
fields. Various electronic decay processes may shorten the lifetime of qubit states in QDs. To model
such processes in QDs we seek to apply the multiconfiguration time-dependent Hartree (MCTDH)3
algorithm in an antisymmetrized version for describing electronic processes as the Auger decay4
known for SA-QDs and the interatomic Coulombic decay (ICD)5.
The intent of this initiating study is to develop a model system for SA-QDs 6. Given previous
results, Gaussians are suitable, because such finite binding potentials can capture the continuum-
like properties of the environment of a QD embedded in an extended wetting layer. Its
parametrization is benchmarked with respect by experimental sizes and energies.
We are also aiming, for future projects, in the description of silicon QDs, colloidal QDs because if
we want to include an exciton recombination in our description, we have to adjust the model to
observables in the experiment (QD size, optical gap, etc.)

1 H.J. Kimble, Nature 453, 1023 (2008)
2 M. Atatüre, D.Englund et al., Nat. Rev. Mater. 3,38 (2018)
3 Meyer, H.-D.; Manthe, U.; Cederbaum, L.S. (1990). Chemical Physics Letters. Elsevier BV. 165
(1): 73–78
4 A. Kurzmann, A.Lorke, M. Geller, NanoLett. 16, 3367−3372 (2016)
5 A. Bande, K. Gokhberg and L. S. Cederbaum, J. Chem. Phys. 135, 144112, (2011) 6 A.
Kurzmann, A.Lorke, M. Geller, NanoLett. 16, 3367−3372 (2016

Speaker: Sara Marando

4:00 PM Characterization of the parameters for gas phase CaMn4O5 cluster. Sample preparation by mass spectrometry

Photosynthesis is the basic process of life as we know it. Despite numerous studies, the details of the natural process are still not elucidated. One of the central problems remains the investigation of the CaMn4O5 cluster, which is a main active part of enzyme Photosystem II (PS II) due to its oxygen-evolving functions [1]. A consistent understanding of the electronic and geometric state of this complex is necessary due to the increasing importance of artificial catalytical complexes. However, the sample production of this cluster from the chloroplast of cyanobacteria and plants is complicated [2], so the selection of the ideal sample plays a crucial role. Thus, we are going to look into the other way of the sample preparation and prepare the CaMn4O5 cluster in a gas phase.

We perform the sample production of the CaMn4O5 cluster in the Ion trap end station [3], located in the BESSY II synchrotron facility at HZB. On this experimental set-up, we are able to produce different types of warm and cold gas-phase clusters using a magnetic sputtering source [4] and detect them with a Time-of-Flight mass spectrometer.
We are using a sandwich of calcium and manganese metal targets, with the latter functioning as perforated sputtering mask. The experiment was performed with different hole sizes for the selection of the optimal parameters of CaMn4O5 production. We conduct this research as the basis for upcoming x-ray absorption spectroscopy (XAS) experiments with the complex.

[1] W. Lubitz et al. Water oxidation in photosystem II, Photosynthesis Research, 2019, 142, 105–125
[2] M. Kubin et al. Soft x-ray absorption spectroscopy of metalloproteins and high-valent metal-complexes at room temperature using free-electron lasers, Structural Dynamics, 2017, 4, 054307
[3] K. Hirsch et al. X-ray spectroscopy on size-selected clusters in an ion trap: from the molecular limit to bulk properties, J. Phys. B: At. Mol. Opt. Phys., 2009, 42, 154029
[4] Haberland et al. Thin films from energetic cluster impact: A feasibility study, J. Vac. Sci. Technol., 1992, A 10, 3266

Speaker: Ms Aryna A. Hreben (Helmholtz-Zentrum Berlin für Materialien und Energie)

4:00 PM Cloud response to volcanic eruptions

Clouds play an important role for the composition of the atmosphere and radiation balance. The influences between clouds and atmospheric processes are numerous and complex which makes them hard to quantify. Especially the presence of different aerosols has a strong impact on cloud formation because aerosols are acting as nuclei for cloud droplets and ice crystals.

Volcanic eruptions lead to a strong local perturbation of the atmospheric composition independent of weather conditions. The emitted aerosols like sulfate or ash affect the formation of different types of clouds. In the DFG research group VolImpact, the impact of volcanic aerosols on atmospheric processes is being investigated in different subprojects. The VolCloud project investigates the effects on liquid clouds (at Leipzig University) and on mixed-phase and ice clouds (at KIT).
The goals of the project are to investigate the climatic effects of volcanic eruptions and to gain general knowledge on aerosol-cloud-interactions by comparing cloud formation with and without volcanic eruptions.

To quantify the impact of volcanic eruptions, the atmospheric processes are being simulated with the ICON (ICOsahedral Nonhydrostatic) model developed by the German Weather Service DWD.
In the presented project the focus is set on new parametrizations of ice formation due to volcanic ash based on previous work. Recent laboratory experiments have shown that the ice nucleation efficiency depends on the mineralogical composition of the ash. These results will be used to investigate the interactions between the volcanic ash plume and mixed-phase and ice clouds.

On the poster an outline of the project and first results of the simulations with ICON will be presented.

Speaker: Melina Sebisch (IMK-TRO)

4:00 PM Controlling atomic interactions and collective effects in thermal vapor cells

Photonic quantum devices based on atomic vapors at room temperature are intrinsically reproducible, scalable and integrable. Besides quantum memories for single photons, one key device in the field of quantum information processing are on-demand single-photon sources. A promising candidate for their realization relies on the combination of four-wave mixing and the Rydberg blockade effect. This has been demonstrated in 2018 [1] and a second generation with improved repetition rate and brightness is currently in development.
Further miniaturization of this experimental set-up is possible by combining photonic structures and atomic vapors on a chip. Those integrated devices additionally lever efficient atom-light interactions below the diffraction limit. In contrast to free-space interactions, atoms aligned within a slot waveguide experience repulsive interactions enhanced by a factor of eight due to the Purcell effect. This leads to a corresponding blue shift, as the atoms are arranged in an essentially one-dimensional geometry, which vanishes above the saturation, providing a controllable nonlinearity at the few-photon level [2].

[1] Ripka et al., Science 362, 6413 (2018)
[2] Skljarow et al., Phys. Rev. Research 4, 023073 (2022)

Speaker: Annika Belz (5. Physikalisches Institut, Universität Stuttgart)

4:00 PM Current-driven writing process in antiferromagnetic Mn2Au for memory applications

Current pulse-driven Neel vector rotation in metallic antiferromagnets is one of the most promising concepts in antiferromagnetic spintronics. We show microscopically that the Neel vector of epitaxial thin films of the prototypical compound Mn2Au can be reoriented reversibly in the complete area of cross-shaped device structures using single current pulses. The resulting domain pattern with
aligned staggered magnetization is long-term stable enabling memory applications. We achieve this switching with low heating of ≈ 20 K, which is promising regarding fast and efficient devices without the need for thermal activation. Current polarity-dependent reversible domain wall motion demonstrates a Neel spin-orbit torque acting on the domain walls.

Speaker: Dr Yaryna Lytvynenko ( Johannes Gutenberg-University Mainz)

4:00 PM Designing an experiment for four-wave mixing with optical nanofiber evanescent dipole-trapped atoms.

The theoretical aspect of the four-wave mixing for a four-level diamond scheme in 87Rb atoms will be discussed. Also, the experimental realization of this study will be presented. In this realization, 87Rb are cooled and further trapped in the vicinity of a nanofiber-based waveguide using a two-color evanescent dipole trap scheme. Then, the four-wave mixing is applied on the trapped atoms in the vicinity of the waveguide giving rise to the better coupling of the generated photon.

Speaker: Mr Zohreh Shahrabifarahani (Okinawa institute of science and technology)

4:00 PM Development of a highly efficient Bessel beam light sheet microscope

Lightsheet fluorescence microscopy (LSFM) is currently one of the most efficient types of optical microscopy exposing the sample to a minimal photon dose. In LSFM, the sample is illuminated by an extremely thin "sheet" of light along the focal plane from which fluorescence is detected, such that only those areas of the sample from which fluorescence is detected are exposed. In the majority of cases, thus sheet of light is created by a cylindrical lens, leading to an extended focal region along the axis parallel to the cylindrical axis and an hour glass shaped focal spot perpendicular to this axis. In order to minimize the thickness of the region from where fluorescence is detected the cylindrical focus is often scanned through the sample, which reduces the overall efficiency of this method. An alternative scheme is Bessel beam microscopy. Here, an extended focus of a pencil lead like shape is created by focusing a thin ring of laser light into the back focal plane of a microscope objective lens. This leads to extended foci as small as 300 nm diameter with up to several 100 µm length, where the central focus is surrounded by concentric rings with a much lower peak intensity. To further minimize contributions from the out-of-focus concentric rings, multi-photon fluorescence excitation is often used. Scanning this pencil lead shaped beam across the sample leads to the currently most homogeneous fluorescence excitation across the detection plane. We have developed and constructed a highly efficient Bessel beam light sheet microscope. The Bessel beam is created by a custom-made double-sided conical lens (an axicon). We will present the otical system layout and demonstrate its performance with recent volumetric image data of biological samples collected with this system. A short outlook to future applications will also be provided.

Speaker: van Merwyk Luis (Biomolecular Photonics Research Group, Faculty of Physics, Bielefeld University)

4:00 PM Development of a tomography system for 3D imaging in the short-wave infrared (SWIR) spectral region

In order to resolve the internal structure of extended biological samples, i.e. entire organisms, organs, or tissue sections, by optical microscopy, these samples require optical clearing in order to become optically transparent. Optical clearing typically involves a harsh chemical treatment process, where samples are first fixed by chemical crosslinking, lipids are removed by transfer from aqueous buffers to 100% alcohol, and finally the removal or bleaching of chromophores. Obviously, this harmful process cannot be extended to living specimen. Light in the short-wave infrared (SWIR) region, however, can penetrate much deeper into biological samples, often up to many millimeters deep - without the need for optical clearing. We are currently developing an imaging system capable of resolving the internal structure of optical samples down to the sub-100 µm scale that utilizes a high pixel-count camera sensitive between 400 - 1700 nm. This will allow us to utilize multiple contrast mechanisms in the infrared spectral region, i.e. absorption and fluorescence of SWIR-active fluorophores to image the water and lipid distribution in these specimen as well as specifically labeled molecular structures. Our current status with regard to these developments will be detailed and explained, and a short outlook to future applications will be provided.

Speaker: Sylvia Steinecker (Biomolecular Photonics Research Group, Faculty of Physics, Bielefeld University)

4:00 PM Development of an active transverse energy filter (aTEF) for background reduction at the KATRIN experiment

The KATRIN experiment at the Karlsruhe Institute of Technology (KIT) aims at the direct measurement of the electron neutrino mass with 0.2eV/c² sensitivity. The high luminosity windowless gaseous molecular tritium source together with the magnetic adiabatic collimation of the electrostatic (MAC-E) filter technique allows for precision endpoint spectroscopy of the tritium beta decay. The analyses of the first and second tritium campaign yield an upper limit of mν<0.8eV (90% C.L.) (Nature Physics 18 (2022) 160).

Despite the advances in lowering the background rate, e.g. by implementation of the shifted-analysing-plane mode (Eur. Phys. J. C 82 (2022) 258), further background reduction measures are required.
The background is assumed to mainly consist of electrons released in the spectrometer, either from the de-excitation of highly-excited Rydberg atoms or from autoionizing states, which originate from alpha-decays in the spectrometer walls. Their kinetic energy at the detector is indistinguishable from tritium beta decay electrons, but they feature a much narrower pitch angle distribution.

We introduce research and development of the active transverse energy filter (aTEF, arXiv:2203.06085) as a concept that allows to discriminate electrons at the detector based on their pitch angle and can differentiate between signal and background electrons in KATRIN.
The contribution will present our proof of principle of microchannel plate-based passive and active transverse energy filters as well as our first Si-PIN-diode based prototypes and their angular-dependent detection properties in a dedicated test setup.
The work of the speaker is supported by BMBF under contract number 05A20PMA and Deutsche Forschungsgemeinschaft DFG (Research Training Group GRK 2149) in Germany.

Speaker: Mrs Sonja Schneidewind (University of Münster)

4:00 PM Development of manufacturing processes for coordinate-based 3D μ-standarts

An important contribution to the success of micro- and nanotechnologies was and is the possibility of being able to visualize and measure objects on this scale. The calibration of 3D-microscopes today requires not only the calibration of the side and height scales, but also the calibration of the flatness error of coordinate planes as well as the shear of coordinate axes. To meet these requirements, suitable standards and reference metrology are needed. The standards currently available on the market for optical microscopes are for different individual calibration steps (lateral, height steps, shape standards).

The 3D-standarts combine the properties of the commercially available standards and are therefore universally applicable. The advantage of this 3D-standards is that the calibration factors for all three axes and even the coupling factors between them can be determined in one measuring and evaluation step. Otherwise, these factors must be determined separately, e.g., with step height and 1D-/2D-grid standards, which means a multiple of measurement and evaluation effort and thus costs.

With this alternative calibration approach, geometric misalignments can be determined using 3D-reference structures with known object coordinates. The approach is based on the principle of measurement marks, as used in close-range photogrammetry, where the actual size of an object can be calculated from the comparison of the object with the measurement mark. Since the 3D-coordinates of the marks on the reference structure are known, the calibration process involves a geometric transformation of the measured object coordinates of the marks to the known object coordinates of the marks according to the calibration model.

Currently used 3D-standarts are produced with FIB [1,2]. Each standard is therefore a cost-intensive custom-made product that also requires time-consuming calibration. Especially for larger structures for the calibration of optical 3D-microscopes, production using FIB is not feasible.

Therefore, wafer-based mask processes for the fabrication of 3D-standarts are to be developed so that many structures can be reproducibly fabricated and adapted to the respective device to be calibrated. The aim of the project is to provide both a validated, wafer-based manufacturing process for 3D-standarts in different sizes and a calibration strategy that ensures traceable reference measurement in verifiable accuracy levels.

First results were achieved by stepwise build-up of silicon oxide layers in combination with a dry etching process. In this way, two-level pyramid structures can be produced onto which the marker for calibration can be applied with the help of lift-off. These structures can be produced from a size range of 5µm edge length for use in the SEM, up to edge lengths of 225µm for optical 3D-microscopy.

However, the structures have a slope angle of about 80°, which works well for calibration of 3D-microscopes, but for SEM calibration the angle must be <70° to provide enough height information for height calibration. To lower the slope angle further, additional etching methods will be evaluated in the further course of the project.

1. M. Ritter et al: A landmark-based 3D calibration strategy for SPM. Meas. Sci. Technol. 18 (2007) pp. 404–414.
2. M. Hemmleb at al: Automated geometric SEM calibration, GIT Imaging & Microscopy 1/2015, pp. 42-44.

Speaker: Celina Hellmich (Physikalisch Technische Bundesanstalt Germany)

4:00 PM Development of Microfabrication processes for a scalable Multilayer Surface Electrode Ion Trap Quantum Computer

Ion traps are promising candidates towards scalable quantum computer. One of the possible designs is the multilayer surface electrode ion traps[1]. The different processes involved in realising it are UV photolithography, Electroplating , Reactive Ion etching and more. Research and development towards the scalable quantum computer is tried with TSVs (through substrate vias) and Flip Chip Bonding for packaging. A solder free thermocompression method is proposed in [2] using gold stud bumps for flipchip bonding , but it brings a risk of damaging the ion trap. An approach with gold micrograss structures in the place of stud bumps is tested for damage free ion trap while bonding.

[1]A. Bautista-Salvador et al. New J. Phys. 21, 043011 (2019), Patent DE 10 2018 111 220 (2019)
[2]M. Usui et al., "Opto-electronic hybrid integrated chip packaging technology for silicon photonic platform using gold-stud bump bonding, (ICEP-IAAC) pp. 660-665 (2015)

Speaker: Ms Nila Krishnakumar

4:00 PM Direct spectroscopic identification of reactive metal-oxygen species

In transition metal-oxygen species, the way the oxygen atoms are bonded to the metal center is found to play a significant role in their reactivity, in view of different types of oxygen ligands and unusual oxidation states.$^{[1,2]}$ In particular, finding of compounds that present transition metals with unusual oxidation states or reactive oxygen species (superoxido, peroxido and oxygen centered radical) is of great scientific and technological interests, as they have key applications as oxidizing agents, catalysts, or reaction intermediates.$^{[1,2]}$
Here, we use X-ray absorption spectroscopy (XAS) at the oxygen K and metal L$_3$, M$_3$ or N$_3$ edges of [MO$_n$]$^+$ systems (M = transition metal, $n$ = integer) to identify the spectroscopic signatures of oxygen ligands and assign the oxidation state of the metal.$^{[3,4]}$ The [MO$_n$]$^+$ species in the gas phase are produced by argon sputtering of a metal target in the presence of oxygen. The cationic species are mass selected and accumulated in an ion trap. X-ray absorption spectra are then recorded in partial ion yield mode.$^{[5]}$ Our ion trap instrument is installed at the undulator beamline UE52-PGM at the Berlin synchrotron radiation facility BESSY II.
Reactive species, such as the superoxido, the ozonido, the oxygen centered radical and species containing high-valent transition metals, are analysed in stable conditions in the ground state inside the cryogenic ion trap. This method is here demonstrated to be an important tool to identify oxygen ligands, offering direct access to element specific electronic structures.

References
[1] Y. X. Zhao, et al., Phys. Chem. Chem. Phys. 13, 1925–1938 (2011).
[2] S. Riedel and M. Kaupp, Coord. Chem. Rev. 253, 606–624 (2009).
[3] M. da S. Santos, et al., Angew. Chem. Int. Ed., e202207688 (2022).
[4] M. G. Delcey, et al., Phys. Chem. Chem. Phys. 24, 3598–3610 (2022).
[5] K. Hirsch, et al., J. Phys. B: At., Mol. Opt. Phys. 42, 154029 (2009).

Speaker: Mayara da Silva Santos (Helmholtz-Zentrum Berlin für Materialien und Energie)

4:00 PM Droplets evaporation on chemically patterned surfaces

The evaporation of fluids on the different patterned surfaces is omnipresent in nature. A
comprehensive study of the evaporation process coupling with the wetting effect through modeling
will give us a complete understanding of the underlying mechanisms and help us construct a digital
twin, enabling us to control the whole system. The poster is divided into two parts. Firstly, based on
the idea of minimum surface, a theoretical model is established to describe the three-dimensional
droplet shape with straight edges and sharp corners on a polygon-patterned substrate in quasi-
equilibrium state. This kind of setup is widely used in droplet sampling for high-throughput
screening of live cells and chemical reactions. We relate the volume of the shaped-droplet to its
height, aiming to address the challenge of measuring the volume of evaporation droplets with usual
experimental techniques. The proposed model is compared with phase-field simulation and
experiments. Secondly, a Cahn-Hilliard phase field model is utilized to describe the diffusion
dominated evaporation process of multi droplets. Through this model, we investigate the effect of
the key parameters including the humidity, volume, droplet position/distance/numbers, liquid type/
concentration etc. on the evaporation process. Our aim is to identify an optimal condition for
culturing cells and sample preparation on Droplet Microarray (DMA) through the digital twin
system.

Speaker: Zhang Hongmin (IAM, KIT)

4:00 PM Flat-field correction for dynamic processes

Using hard coherent x-rays, as produced in PETRA III at DESY, objects of μm length-scale can be imaged with full-field phase-contrast imaging. A recorded single-pulse hologram of the object under investigation in a lens-less imaging setup is disturbed by illumination artifacts. The origin of these artifacts lies in aberrations in the optics, such as figure errors and surface roughness. For further analysis, the illumination artifacts have to be removed, which is achieved by a flat-field correction. Therefore, the x-ray image of the object of interest is divided by an empty-beam image. This approach assumes temporal stability of both illumination and object. For an experiment conducted at beamline P02 at PETRA III, in addition to vibrations in the beamline's optical components, the object itself incorporates dynamic movements. The common case of flat-field correction can be improved by recording an empty-beam image series. With principal component analysis (PCA) of the image series and a careful selection of the principal components, a synthetic flat-field can be reconstructed for each object image.

Speaker: Thea Engler (Deutsches Elektronen Synchrotron DESY)

4:00 PM Global fits for Dark Matter searches with GAMBIT

The unambiguous detection of dark matter requires compatible signals from complementary searches. In this regard, global fits can help us understand if observed excesses and limits agree with each other. To this end, we present the global fitting software GAMBIT (Global and Modular BSM Inference Tool). We exploit GAMBIT’s modularity to implement a new likelihood for the AMS-02 antiproton data, which uses the deep neural network Dark Ray Net for fast simulation of primary and secondary antiproton fluxes. We present the impact of this newly implemented likelihood on the Scalar Singlet Model and discuss whether there is evidence for a dark matter signal in AMS-02 antiproton data.

Speaker: Ms Sri Sankari alias Sowmiya Balan (RWTH Aachen University)

4:00 PM High-Frequency ESR Studies on the Frustrated quasi-1D Spin-1/2 Chain PbCuSeO$_4$(OH)$_2$

We report high-frequency ESR studies on a powder sample of the frustrated quasi-1D spin-1/2 chain material PbCuSeO$_4$(OH)$_2$, isostructural to the well studied natural mineral linarite (PbCuSO$_4$(OH)$_2$). Magnetisation data show the evolution of a magnetically ordered phase below $T_{\rm N}$ = 4.3~K and a spin-flop transition at $B_{\rm SF}$ = 2.8~T.
ESR measurements on a loose powder evidence a gapless linear excitation mode within the ground state, which can be traced across the spin-flop transition, as well as two linear excitation modes within the in-field phase with a zero field gap of $-31\pm9$~GHz and $32.9\pm1.4$~GHz. Measurements on a fixed powder reveal a gapped magnon mode in the ground state with a zero field splitting of $70\pm20$~GHz. This mode may be accounted for by assuming an excitation of a spiral spin order in the ground state.
Tracing the resonance positions with temperature suggests an easy-axis type anisotropy with the paramagnetic g-factors 2.3 and 2.07. Changes in resonance position evidence the onset of short range fluctuations at 70~K and the evolution of orthorombic anisotropy.

Speaker: Ms Rahel Ohlendorf (Kirchhoff Institute for Physics, Heidelberg, Germany)

4:00 PM Hot Carrier Injection and Bias Temperature Instability in SiC Transistors

N- and p-channel metal oxide semiconductor field effect transistors (N-MOSFETs, P-MOSFETs) have a wide range of applications today but have their limits to operate in harsh environments with temperatures above 300°C or with high rates of radiation. Transistors realized with Silicon Carbide (SiC) as compound semiconductor are candidates to overcome these issues and have been used as power semiconductors for years already. Current research efforts focus on microscopic degradation mechanisms in SiC transistors, known as Hot Carrier Injection (HCI) and Positive Bias Temperature Instability (PBTI) in NFETs and negative BTI (NBTI) in PFETs. We investigated the reliability of SiC NFETs and PFETs with respect to HCI, NBTI and PBTI degradation models by adapting stress voltage levels and temperature.
The JEDEC standards describing the procedures for measuring the degradation mechanisms in Si integrated transistors were used to set up the corresponding measurements for SiC transistors. This allows the comparison of the degradation behaviour between the two different materials.
The results so far show interesting differences in the aging especially the Hot Carrier Injection in NFETs compared to equivalent sized silicon based transistors.
The derived models are able to be used in SPICE models to depict the physical behaviour of SiC Integrated transistors in IC simulation software.

Speaker: Sophie Winkler

4:00 PM Lattice-driven femtosecond magnon dynamics in α-MnTe investigated with linear spin wave theory

The femtosecond sublattice dynamics in the antiferromagnetically ordered phase of the semiconductor $\alpha$-MnTe are calculated using the linear spin wave theory [1]. We assume that collective lattice vibrations generated by laser pulses induce an oscillating Heisenberg coupling and thus a driving that generates magnons. The calculated antiferromagnetic order parameter shows damped coherent longitudinal oscillations, which decay due to dephasing. We also include a phenomenological dissipative term to describe spin-lattice relaxation processes, which lead to relaxation back to thermal equilibrium. In addition, we provide approximate analytic solutions of the differential equations to understand the effect of the amplitude, frequency, and lifetime of the driving.

[1] K. Deltenre, D. Bossini, F. B. Anders, and G. S. Uhrig, Phys. Rev. B 104, 184419 (2021)

Speaker: Kira Deltenre (Department of Physics, TU Dortmund University, D-44227 Dortmund)

4:00 PM Matter-Antimatter Asymmetry and Composite Higgs Models

Why do we exist? How the observed Baryon Asymmetry in the Universe (BAU) came to be cannot be explained within the Standard Model of Particle Physics (SM). While the Electroweak Phase Transition (EWPhT) has all the ingredients nececessary for baryogenesis, it lacks quantitatively in two points: the phase transition is not strongly first order and the SM does not provide enough CP-violation. This can be remedied by introducing new physics, e.g. an additional scalar singlet $S$. A particularly well-researched class of Electroweak Baryogenesis (EWBG) models feature a $Z_2: S\rightarrow -S$ symmetry of the singlet that is spontaneously broken around the electroweak scale. However, such a scenario generically leads to phenomenologically problematic domain walls.

Here, a thermal history in which the $Z_2$ symmetry is not restored at high temperatures is envisioned, as accomplished by introducing a $S^6$ operator. This effective field theory (EFT) can be understood as the low-energy tail of a more complete theory, such as a Composite Higgs (CH) model. In CH, the Higgs is thought of as a composite of new fermions and described as a pseudo-Nambu-Goldstone Boson of a spontaneously broken global symmetry, making its mass small and solving the EW Hierarchy Problem. As a possible UV-completion to the $Z_2$ non-restoration (SNR) scenario, a $SO(6)/SO(5)$ CH model is employed. The scalar potential and Yukawa interactions can be obtained in spurion analyses and spontaneously CP-violating terms arise. Models with SM fermions embedded in (1), 6, 15 and 20′ representations of SO(6) are compared.

The EFT parameter space where a strong first order EWPhT can be obtained is matched to the most promising CH model, finding that all conditions for EWBG can be fulfilled and the correct BAU may be generated.

Speaker: Aika Tada (MPI Heidelberg)

4:00 PM Measuring correlated phases in encapsulated bilayer graphene via graphite contacts

Encapsulation of graphene into in hexagonal Boron Nitride (hBN) has been central to a lot of the research done on graphene in the recent years. Furthermore, graphite top and bottom gates can be added to increase the sample quality. In Bernal stacked bilayer graphene, gate tuning allows to tune control the charge density as well as the out-of-plane electric field independently from one another, which led to the observation of many intriguing many-body phases. Recently, a cascade of new correlated phases including Stoner half and quarter metals [1-3], correlated insulators [1] and superconductivity [2] were revealed at large electric fields in trigonal warped bilayer graphene.

These findings have led to an increased interest in further research on exploring the complex phase diagram of Bernal bilayer graphene. The extent in to which this phase space can be further explored addressed is amongst other parameters however limited by the maximum electric field and thus by the maximum values of gate voltages that can be applied to the sample without breaking through the dielectric. With the aim of increasing these maximum voltages, we have explored the method of using graphite contacts to contact bilayer graphene flakes within van-der-Waals heterostructures [1]. Using graphite contacts instead of commonly used 1D edge contacts [4] removes the necessity to etch into the hBN flakes. This etching process would locally reduce the thickness of the dielectric and had therefore previously been a limiting factor for the applied electric fields.

[1] Seiler, A. M. et al., Nature 608, 298–302 (2022)
[2] Zhou, H. et al. Science 375, 774-778 (2022)
[3] de la Barrera, S. C. et al. Nature Physics 18, 771–775 (2022)
[4] Wang, L. et al. Science 342, 614-617 (2013)

Speaker: Ms Isabell Weimer (Georg-August-Universität Göttingen)

4:00 PM Narrow-linewidth Laser Systems for the 1S0-3P2 and 1S0-3P0 Clock Transitions in Strontium

Recent breakthroughs with ultracold-atom-based programmable quantum simulators have started to show the potential of tweezer arrays as a quantum simulation platform.
A promising application is the simulation of many-body systems like the Ising or Hubbard models.
Our goal is to unite these two capabilities in a novel programmable quantum simulator based on the alkaline-earth atom strontium.
A crucial part is realising two-level spin systems based on ultranarrow optical clock transitions. Strontium offers various transitions suited for this purpose. We focus on the 1S0-3P2 clock transition at $671$ nm which can be magically trapped by tuning the angle of an applied magnetic field. Additionally, we plan to use the 1S0-3P0 clock transition at $698$ nm. This poster presents the generation and stabilization of the $671$ nm narrow linewidth laser light. For this purpose, a home-built external-cavity diode laser is frequency-stabilized to an ultrastable reference cavity.
Furthermore, this poster presents the layout for frequency stabilisation of the $698$ nm laser light, locked to the same cavity.

Speaker: Alexandra Beikert

4:00 PM Numerical simulation of topologically optimized open-pore metal foams using a phase-field approach

The research project is located in the context of lightweight materials design and is
concerned with the topology optimization of novel foams with regard to best possible foam
structures under mechanical compressive/tensile load. The methods for topology optimisation are
based on the computer-aided design and characterisation of digital foam structures. The focus of the
project is to create a digital model that provides insight into the relation of microstructure and
properties of open-pore metal foams, and which is intended to accompany the manufacturing
process of these solid foams.
Controlling the microstructure formation in foams is key to tailoring the resulting structures with
defined geometries and properties.
This requires understanding how different pore structures influence the set of physical properties
associated with varying requirements on components and material, depending on the later
application. In this work, the foam skeleton structure formation determined by curvature
minimization is studied numerically. In order to generate topologically optimized foam structures, a
digital model is utilized. To predict the microstructure evolution, we use a numerical simulation
method based on a phase-field model to perform large-scale parallel simulations of 3D cellular
structures. Phase-field simulations focusing on the generation of a large set of varying structures
allow for investigation of the design and loading conditions relating to topology in the next project
step. Considering this set of different structures, the impact of individual foam parameters like
ligament size, overall density, or pore size distribution can be studied separately, with regard to their
impact on overall morphology. The modeling approach yields data sets of optimized foam structures
with different topological and morphological characteristics. Making use of the in-project applied
database, the interlinking of experimentally determined requirements on mechanical properties and
digitally generated structures can further enhance the optimization of the tailor-made foam
structures.

Speaker: Jana Holland-Cunz (IAM, KIT)

4:00 PM Optimizing TES detection systems for extremely low background dark matter searches

Transition Edge Sensors (TES) are superconducting microcalorimeters that can be used for
single-photon detection at extremely low backgrounds. When they are within their supercon-
ducting transition region ($\sim140~$mK for the TES in this work) small temperature fluctuations
- like the energy deposited by single photons - lead to large variations in resistance. These
variations can be measured using Superconducting Quantum Interference Devices (SQUIDs).
This exciting technology will be used as a single-photon detector for the upcoming ALPS II
experiment, a light-shining-through-walls experiment at DESY Hamburg, searching for Axion-
Like Particles (ALPs), which are possible Dark Matter (DM) candidates. At ALPS II, the
detector needs to detect single photons with a wavelength of $1064~$nm at a rate of $\sim10^{-5}~$Hz
leading to very stringent dark count requirements. Therefore, the main challenges in com-
missioning a TES for ALPS II involve determining and increasing its detection efficiency and
reducing dark counts as well as backgrounds introduced by e.g. black-body radiation. Due to
the very low dark count rates in our setup, our TES system might be viable for direct DM
searches at sub-MeV masses using electron-scattering of DM in the superconducting material,
as well.
In this work, the commissioning of a TES for the ALPS II experiment will be outlined, followed
by an outlook on the possible application of TESs as detectors for direct DM searches.

Speaker: Christina Schwemmbauer (DESY)

4:00 PM Phase-transition in MoTe2 tracked by time-of-flight momentum microscopy

We have performed a comprehensive study of the temperature-induced phase-transition in transition metal dichalcogenide (TMDC) Mo1-XWXTe2 using ARPES, including linear and circular dichroism in the angular distribution (CDAD/LDAD), X-ray photoelectron diffraction (XPD) and spectroscopy (XPS) of the core-levels, Raman and X-ray diffraction (XRD) measurements at
different temperatures. Based on detailed structural information from XRD measurements,
calculations of XPD patterns were made using the Bloch-wave approach. It was found that the orthorhombic phase of MoTe2 shows inversion symmetry breaking and topological states and therefore has wide spectrum of potential applications.

Speaker: Olena Fedchenko (JGU, Institut Für Physik)

4:00 PM PHYSIKERINNEN: Zahlen und Fakten

Aktuelle Daten zur Situation von Physikerinnen in Deutschland sowie deren Entwicklung in den letzten Jahren werden präsentiert. Während des Studiums und im Berufsleben treten immer wieder Fragen auf wie: „Werden Frauen immer noch benachteiligt?“ oder „Gibt es mittlerweile genügend weibliche Vorbilder in der Physik – gerade auch in Bezug auf die Vereinbarkeit von Familie und Beruf?“ und „Wie viele Physikerinnen gibt es eigentlich in Deutschland?“. Der Arbeitskreis Chancengleichheit (AKC) der Deutschen Physikalischen Gesellschaft (DPG) stellt solche Daten regelmäßig auf der Basis des Materials des statistischen Bundesamts zusammen und ergänzt sie durch eigene Erhebungen der DPG. Die aktuellen Daten werden vorgestellt und diskutiert.

Speaker: Dagmar Paarmann (AKC)

4:00 PM Rydberg atom interactions at the interface of an optical nanofiber

Rydberg atoms are considered as one of the most promising candidates for quantum technologies. We have realized Rydberg atom excitation using light guided by an optical nanofiber (ONF). The large evanescent field resulting from the strong confinement of light in the ONF serves as a good platform for atom-light interactions. Our experiment consists of an ONF overlapped with a cloud of Rubidium-87 atoms cooled and confined by a magneto-optical trap (MOT). The atoms from the MOT are excited to Rydberg state via a two photon process, with one photon from the cooling beams and the other guided through the ONF. Atoms excited to the Rydberg state are lost from the MOT, leading to a reduction in the fluorescence measured, which we use as an indirect measurement of the rate of excitation. We could utilize our system for further studies on surface-atom interactions and extend our system for trapping atoms.

Speaker: Ms Aswathy Raj (Okinawa Institute of Science and Technology (OIST), Japan)

4:00 PM Semi-visible Dark Matter Signatures

The existence of dark matter has been known for many decades, but its nature remains one of the biggest mysteries of our Universe, suggesting new physics beyond the Standard Model. We consider a class of models that introduces new, dark particles that are strongly coupled to each other and only coupled to the Standard Model through a new massive exchange particle. The dark particles can potentially explain the dark matter abundance in our Universe, while the new exchange particle can be produced in high-energy particle collisions and result in signatures that are partially invisible and therefore distinctively different from standard model signatures. We study this class of models in the context of new data from dedicated searches at the LHC and discovery potential at future searches and experiments.

Speaker: Nicoline Hemme (Karlsruher Institut für Technologie)

4:00 PM Sensitivity studies for eV scale sterile neutrino searches with KATRIN

KATRIN has recently reported an unrivalled sub-eV direct constraint of the neutrino mass from tritium beta-decay spectrum measurements [1]. Along with the neutrino-mass search, KATRIN has published first results of searching for a fourth (sterile) neutrino with a mass in the eV-range using the precision beta-decay spectra[2],[3].

The fourth neutrino mass-eigenstate introduces an additional branch into the tritium $\beta$-spectrum which manifests as a kink in the model of the differential spectrum. Position and amplitude of this kink correspond to the sterile neutrino mass $m_4$ and effective mixing angle sin$^2(\theta) = |U_{e4}|^{2}$, respectively. In this work sensitivity studies to light sterile neutrinos based on additional science runs and the effect of systematic uncertainties are presented. The analysis region is a two-dimensional parameter space given by $m_4^2<1000$ eV$^2$ and sin$^2(\theta)<5\times 10^{-1}$. A scanning grid with 50$\times$50 points in the ($m_4^2$, sin$^2(\theta)$) plane is chosen and sensitivity contours are calculated within this parameter space. Future strategies for a combined analysis of successive measurement campaigns are discussed.

References:
[1] Direct neutrino-mass measurement with sub-electronvolt sensitivity, KATRIN Collaboration, Nature Phys. 18 (2022) 2, 160-166
[2] Bound on 3+1 Active-Sterile Neutrino Mixing from the First Four-Week Science Run of KATRIN, DOI: 10.1103/PhysRevLett.126.091803,(2021), KATRIN Collaboration
[3] Improved eV-scale sterile-neutrino constraints from the second KATRIN measurement campaign, DOI: 10.1103/PhysRevD.105.072004},(2022), KATRIN Collaboration

Speaker: Ms Shailaja Mohanty (IAP, Karlsruhe Institute of Technology)

4:00 PM Simulating Arctic Clouds using the Numerical Weather Prediction Model ICON

The Arctic is a fascinating part of the Earth, remote and inaccessible but so important for the climate. Its now evident role in climate change, such as the loss of sea ice concentration, makes it an even more attractive place to study. The Arctic climate is a highly coupled state between the open ocean, the ice sheet and the atmosphere where they feed back to each other. While the loss of sea ice s a current hot topic where we now understand more and more, the atmosphere, and especially clouds are still challenging topics. Clouds impact the climate in drastic ways, the incoming solar radiation is reduced by the scattering of cloud water and ice while the longwave radiation to the surface is increased by downwelling heat from the clouds, the sum of these interactions makes the clouds cool the Earth on average. In the Arctic however, this is an even more complicated interplay where the reflectivity of the ice renders the effect of clouds positive, meaning the presence of clouds warm the surface. Arctic cloud effects are thus vital when considering surface energy budgets as well as for the overall climate. With the projection of an increased cloud cover in the Arctic with higher temperatures this interaction between clouds and the sea ice becomes more important.

Looking at clouds on a microphysical level, how they are formed and how they develop, we can, for example, deduce where the cloud was formed by looking at what aerosols the cloud contain. Aerosols are suspended particles such as pollen, seasalt, dust and air pollutants. In the presence of water these particles grow into cloud droplets which form clouds but the relative amount of these aerosols in the cloud can tell us if the cloud was formed for example over seas or by planes passing by, as in the case of contrails. These aerosols impact the cloud in many ways such as their lifetime – how long the cloud survives, if it precipitates, if it freezes into an ice cloud or how much sunlight it can scatter. These effects are termed aerosol effects and their interactions with clouds is then the aerosol-cloud interactions. In the Arctic, there are not many industries present, nor is it close to any dust sources or civilisations, thus this area is supposedly very clean. However, from ship based campaigns in the Arctic we have seen that clouds are very abundant, even more so than at lower latitudes, and survive for days indicating we don’t yet know the full story.

To explore these clouds and the aerosol effects, we are using a Numerical Weather Prediction model called ICON (ICOsahedral Nonhydrostatic Model), developed by KIT together with the German weather service, DWD, and Max Planck Institute, MPI for Meteorology. This model can be used for climate projections,weather forecasts as well as atmospheric research. The dynamics of the atmosphere is evolving in time as well as processes on smaller scales than what we resolve in the model which are parameterised. On top of this we couple an aerosol module developed at KIT called ART, where aerosol dynamics as well as chemistry are included, which provides a prognostic aerosol concentration. Using a model has many advantages as we can tweak inputs such as aerosols, and watch how the model behaves, how the situation has changed and from this deduce aerosol impacts and microphysical processes in the clouds. This will give an improved understanding on how these clouds behave which will lead to a better representation of these clouds in weather forecasts, shedding more light on the causes and effects of Arctic Amplification and Climate Change. Here, I will give an intro to Arctic clouds and especially focus on multilayered cloud systems, showcasing aerosol impacts on clouds when perturbing the aerosols in the Arctic.

Speaker: Gabriella Wallentin (IMK-TRO)

4:00 PM Steady-state operation of a cell-free genetic band-detection circuit

Over the past decade, synthetic gene networks have been used extensively to explore principles of biological pattern formation as they play a decisive role during biological growth and development processes. Pattern-forming circuits are also of great interest for the development of future biomaterials that respond to and differentiate autonomously with respect to their environment.
Here, we report on a bottom-up approach to design and analyze a cell-free genetic circuit based on an incoherent feed forward loop (IFFL-2), which is expected to produce a three-stripe pattern in response to an input gradient. In our work, we first simulated the behavior of the circuit and explored relevant parameters using a genetic algorithm approach. We then separately investigated the behavior of the three nodes comprising the IFFL-2 network in a bacterial cell-free gene expression system which was produced from a genome-engineered bacterial strain lacking LacI expression. We showed that the genetic circuit functioned as expected under non-equilibrium conditions in microfluidic ring reactors, whereas it fails to perform in bulk experiments in closed reactors. We showed that the non-equilibrium conditions are of necessity to establish the double-repression cascade which was the essential element of the genetic circuit. We used six neighboring ring reactors to establish a “virtual” morphogen gradient by supplying the reactors with decreasing amounts of the transcription factor σ28, corresponding to the different positions within an exponential morphogen gradient. We finally demonstrated that our IFFL-2 circuit, when operated in the microfluidic system, shows the correct gene expression response that is required for stripe-formation in a spatial context.

As the operation in microfluidic reactors would be at least laborious and time consuming to use for the realization of biomaterials that can differentiate autonomously in response to externally supplied chemical cues, the next step is to work on materials with simple and efficient supply lines (like vasculature). Those will be needed to implement cell-free metabolic processes and self-regeneration to enable operation of these systems over longer periods of time under non-equilibrium conditions.

Speaker: Anna Jäkel (TUM)

4:00 PM Temperature dependence of Raman scattering of Ge and GeSn layers

Germanium (Ge) and GeSn materials are very promising candidates for complementary metal-oxide-semiconductor electronics and photonics applications due to their high electron mobility and the possibility to achieve direct bandgap by tuning composition or strain. These are excellent perspectives for devices such as lasers, light-emitting diodes, photodetectors, and modulators. The vibrational properties of these materials can be related to the high quality of the material required for applications, as well as to electron-phonon and phonon-phonon interactions. To this aim, Raman spectroscopy is a well-suited technique that provides non-destructive testing and detailed information about thermal expansion, and anharmonicity.
In this work, Raman spectroscopy was used to study Ge and GeSn layers, through the analysis of the spectra in terms of peaks position, width, and asymmetry of the lineshape. Temperature dependence was measured from 80 to 573 K and analyzed by a model that considers thermal expansion, anharmonicity of the vibrations, and strain.
Ge layers were grown by Chemical (CVD) and Physical (PVD) vapor deposition process. Narrow peaks in high-quality epitaxially CVD-grown layers that evolve with temperature increase were observed. In polycrystalline samples deposited on SiO2 by PVD, Ge peaks were asymmetric and two times wider than on the Si substrate. The polycrystalline samples have the strongest anharmonicity, although it does not differ from the crystalline materials by more than 15%.
In thin, compressively strained GeSn alloy layers, grown by CVD with Sn concentration in the range of 5%-14%, the anharmonicity is more significant than in the polycrystalline Ge, and independent of the Sn content. These results will assist future developments for optoelectronics and thermoelectrics in semiconductors in group-IV semiconductors.

Speaker: Diana Ryzhak (IHP – Leibniz-Institut für innovative Mikroelektronik)

4:00 PM The influence of displacement damage on helium interaction with and retention in tungsten

In a future nuclear fusion reactor, the inner wall components facing the deuterium-tritium-plasma will be subjected to a significant flux of helium (He) as a product of the fusion reaction. Tungsten (W) is considered as the most favorable plasma-facing material because of its good thermal properties, low solubility for hydrogen isotopes, and the high energy threshold for physical sputtering. However, He bombardment is known to degrade the mechanical and thermal properties of W and various studies have shown a complex influence of the presence of He on the retention of hydrogen isotopes in W. In order to make sound predictions for future nuclear fusion devices such as ITER, a fundamental understanding of the He-W interactions is necessary.
In this study, the influence of pre-existing displacement damage on the early stages of helium interaction with tungsten as well as the resulting defect creation through He clustering mechanisms was investigated experimentally. Samples were irradiated with 20.3 MeV W ions to different displacement-damage levels of 0.005, 0.01 and 0.1 displacements per atom (dpa). Displacement-damaged samples were exposed to a He plasma at room temperature at a He flux in the range of 10¹⁸ He/m²s to fluences of up to 10²² He/m² together with pristine W samples. He ion energy of 100 eV was used to remain well below the threshold for displacement damage creation in the bulk. Elastic recoil detection analysis (ERDA) shows that the He retention in the damaged samples is one order of magnitude larger than in the undamaged sample. Detailed He depth distributions were obtained by stepwise removal of near-surface layers (via anodic oxidation followed by the dissolution of the oxide) and subsequent ERDA measurements of the remaining He content. Pre-damaged samples show a significantly faster decrease in He concentration with depth than the undamaged sample, indicating that He is efficiently stopped from diffusing into deeper regions beyond 30 nm by pre-existing defects. The undamaged sample exhibits a lower He concentration in the near surface region and a flatter distribution of He up to a depth of 100 nm. Since our data shows the displacement damage level to be the determining factor of the on the He uptake and retention we conclude that He self-trapping mechanisms do not yet have a strong effect on the He diffusion depth in W at the low He fluxes used in this study.

Speaker: Annemarie Kärcher (Max-Planck-Institut für Plasmaphysik, Technische Universität München)

4:00 PM The QSNET-Network of high-precision clocks and the quest for light dark matter.

Beyond the Standard Model, scalar field dark matter may induce distinct variations in fundamental constants, be it through temporal oscillations or transient changes. With a novel approach, the QSNET project aims to find evidence of new physics by linking observed variations in atomic transition frequencies in a network of ultraprecise atomic, highly charged ion (HCI) as well as molecular clocks to variations in both the fine-structure constant and the electron-to-proton mass ratio. Comparing two from up to seven clocks located at four English institutions in a fibre-linked networked approach, allows for the measurement of frequency ratios with unprecedented precision. Here we give a short overview of the physical background of QSNET, the proposed configuration and coupling of the different clocks, as well as their anticipated performance and scientific goals. Implementing the Lomb-Scargle method allows for a preliminary assessment of QSNET's potential prospects and limitations in achieving high detection confidence for low-mass scalar dark matter.

Speaker: Saskia Kreienbaum (Humboldt-Universität zu Berlin)

4:00 PM Three-dimensional optical tomography of biomedical tissues

In the field of optical microscopy, the size range of biological and medical samples of interest varies from single biomolecules (nanometer scale) to whole animal organs (centimeter scale). Since this size range spans across 7 orders of magnitude, different optical tools are needed to analyze such samples across these scales. The mesoscopic size range is concerned with the larger structure of samples up to several centimeters. For such large samples, the penetration depth of optical microscopy is limited by the interaction of light with tissue causing absorption and scattering. The amount of scattering depends on the thickness and the transparency of the sample. The larger the sample, the lower is the best achievable resolution. With the use of optical projection tomography (OPT) it is possible to image and reconstruct the internal three-dimensional structures of such large samples. For example entire intact murine organs are visualized without the need for physically cutting the tissue. The sample must, however, be cleared before imaging to improve the penetration depth of the visible light and fully resolve the internal structure. We are currently working on improving the whole mount staining process using indirect antibody labelling for different types of biological samples, i.e. mouse organs, mouse embryos and human nasal polyps. Optical clearing is performed using the organic solvents benzoic acid and benzyl benzoate (BABB) and we are characterising the effect of pre-bleaching the tissue with H202. The OPT setup is combined with a mesoscopic light-sheet microscope to compare the resulting reconstructed images and the resolution of both techniques based on the same sample. OPT is used to characterize and measure the internal structure, i.e. the three-dimensional distribution of blood vessels and calculating i.e. the microscopic vessel density. Our current status of improving the imaging conditions, sample preparation, and the optical setup will be detailed.

Speaker: Jasmin Schürstedt (Biomolecular Photonics Research Group, Faculty of Physics, Bielefeld University)

4:00 PM Time-resolved second-harmonic imaging microscopy: ultrafast processes in ultrathin materials

Internal interfaces between two solids play a decisive role in modern materials sciences and their technological applications. Among the most prominent examples are certainly semiconductor devices which have been miniaturized to such an extent that their optical and electronic properties are determined decisively by the interfaces.

Two-dimensional heterostructures of transition metal dichalcogenides (TMDCs) represent very well-defined and at the same time highly versatile model systems of van-der-Waals interfaces which enable us to investigate the electron dynamics at the interface between two molecularly thin semiconducting layers. Many combinations of two different TMDC materials feature an alignment of the electronic bands which facilitate the separation of photoexcited electrons and holes into different layers through ultrafast charge transfer leading to the formation of so-called interlayer excitons. Moreover, the electronic coupling between the layers can be modified by variation of the stacking angle, which is expected to strongly influence the exciton dynamics.

To investigate the ultrafast charge-transfer dynamics in twisted TMDC heterostructures we use time-resolved second-harmonic generation (SHG) imaging microscopy. As a nonlinear optical technique SHG is particularly suited for the investigation of interfaces and is highly sensitive to symmetries of crystalline samples. This enables us to determine the orientation of TMDC monolayers and, moreover, to probe individual layers of the twisted heterostructures by selecting the proper laser polarization. By imaging the SHG signal via a camera lens on a CCD chip, the method enables pump-probe experiments in µm small structures with a time resolution of 10 fs.

Speaker: Marleen Axt (Department of Physics, Philipps-Universität Marburg, Germany)

4:00 PM Towards a pulsed beam of antihydrogen for tests of the Weak Equivalence Principle for antimatter

The Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AEgIS) collaboration, based at CERN's Antiproton Decelerator (AD) complex, is working towards the production of a pulsed horizontal beam of antihydrogen atoms. The detection of the vertical deflection of such a beam will provide a direct measurement of the gravitational acceleration of antimatter and thus constitute a novel way of probing the Weak Equivalence Principle (WEP).
In 2018, AEgIS has successfully demonstrated the individual production of antihydrogen atoms as a pulsed, isotropic source by means of a charge exchange reaction: antiprotons were captured from the AD inside a Penning-Malmberg trap, further cooled, and combined with positronium atoms, which were previously laser-excited to Rydberg states, to form antihydrogen.
Since then, the Extra Low ENergy Antiproton ring (ELENA) has been installed in the AD complex as an additional decelerator, having commenced its operation in autumn of 2021. ELENA yields an increased number of even colder antiprotons from which AEgIS aims at fully benefiting. For this purpose, the AEgIS apparatus has undergone several upgrades, including a full transformation of the anti-H production into a collinear scheme with a newly constructed production trap and positronium converter, the installation of a new laser system, as well as the complete rebuild and automation of the experimental control system.
Given these improved conditions and the resulting expected increased rates of antihydrogen production, AEgIS is moving towards the formation of a horizontal beam to directly investigate the influence of gravity on the anti-H atoms, profiting by the precise knowledge of the production time in the pulsed scheme. Such a measurement will be a first step towards probing the WEP for antimatter and represent a test of the CPT theorem, which assumes complete symmetry between matter and antimatter systems.
This contribution will give an overview of the status of the improved AEgIS setup and results obtained during the first beam times with ELENA as well as the progress towards the formation of a pulsed beam of antihydrogen.

Speaker: Saiva Huck (CERN, Universität Hamburg)

4:00 PM Towards dynamic measurements of individualized macromolecules

Detailed insight into the dynamics and other functionalities of synthetic polymers on the molecular level is highly desired in advancing nano-technology; however, often, it can be technically challenging. We investigate the dynamics in individualized polymeric chains employing broadband dielectric spectroscopy (BDS). This method revealed altered dynamics under conditions of spatial confinement in the past; however, there is no detailed information about the extent to which the properties of the material change due to individualizing the polymer chains. To address samples of such a small scale, nano-dielectric spectroscopy is developed by refining a nanostructured electrode setup combined with a procedure of chemical surface modification. The latter involves depositing a very regular pattern of gold nanoparticles (AuNPs) of well-controllable size and separation on the nanometer scale. These AuNPs act as anchors for the chemical grafting of end-functionalized polymers (e.g., thiol terminated PEO). To determine the (average) number and conformation of chains grafted to each AuNP, their volume and shape are characterized by AFM.

Speaker: Mrs Alaa Hassan (Universität Leipzig)

4:00 PM Towards experimental detection of crystallization in individualized polymer chains

Although crystallization of polymers has been investigated since decades, it is not yet fully understood. One way to gain more insight is to study the difference between bulk polymer and confined polymer chains with focus on how crystallization characteristics change depending on the size and type of confinement. Until now, most studies have used confinement in thin films or nanopores but the approach to study crystallization and aggregation in individual chains was accessible only to computer simulations.
Since detection of phase transitions in individual polymer chains poses a severe challenge to most experimental methods, the measurement of ensembles of individual chains is desirable. However, maintaining the individual character requires a sophisticated method to separate them. Here, we use block copolymer micelle lithography (BCML) to deposit a regular pattern of well-separated gold nanodots on a silicon substrate in order to chemically graft end-functionalized polymer chains on these nanodots to individualize them. Instead of common thermodynamic methods (which require considerably more sample material), we employ dielectric spectroscopy using a nanostructured electrode arrangement since it is much more sensitive. Albeit being typically considered a dynamics method, it also allows to examine density changes and thus phase transitions of polymers.

Speaker: Mr Wing Kit Or (Peter Debye Institute for Soft Matter Physics, Universität Leipzig)

4:00 PM Towards switchable photon-photon interactions

Since photons are robust carriers of information, photon-based qubits provide a promising platform for efficient error- and resource-reduced all-optical quantum computing [1,2]. When interfacing photons with matter to so-called polaritons, they additionally inherit strong particle-particle interactions [3,4]. By coupling the photons to highly-excited Rydberg states, long storage times can be achieved even in thermal vapours above room temperature [5].

We use non-interacting Rydberg polaritons to store two photons in an atomic vapour and activate the two-photon interaction on demand by driving to a second pair of strongly interacting Rydberg states. After interaction, the photons can be stored or retrieved coherently [1] from their individual polaritonic states.

We have identified a set of suitable Rydberg states in rubidium to facilitate the required interaction properties for the storage and interaction phases. Currently, the different state transitions are addressed in a thermal vapour to benchmark and optimise the em-field sources, pulsing and read-out. Here, the terahertz transition represents a particular challenge but is similarly exciting, since it extends the spectral range used for quantum simulation and computing to a yet seldom utilised but highly relevant part of the electromagnetic spectrum.

[1] PRL 127, 063604 (2021)
[2] Science 318, 1567 (2007)
[3] Nature 488, 57-60 (2012)
[4] J. Phys. B: At. Mol. Opt. Phys. 49, 152003
[5] Nature Communications 9, 2074 (2018)

Speaker: Ms Karen Wadenpfuhl (PI, Universität Hidelbrg and QLM, Durham University)

4:00 PM Traveling wave parametric amplifiers for microwave quantum optics

Traveling wave parametric amplifiers (TWPAs) are not only promising candidates to achieve broadband amplification of small quantum signals at quantum limited noise. Beyond that, they have been successfully applied to realize quantum optics experiments in the microwave regime [Esposito et. al., PRL 128(15), 2022] and might even become key tools to generate multi-mode entanglement. However, in contrast to resonant devices traveling wave amplifiers can also allow for additional nonlinear processes involving higher sidebands which can have a detrimental impact on the entanglement of signal and idler mode. Therefore, an adequate theoretical description capturing the impact of sidebands as well as higher harmonics is crucial. Hence, our work focuses on extending the standard treatment of the mode dynamics at the first sideband and investigating the signature of sidebands and higher harmonics on gain and entanglement characteristics. Our results show that these unwanted sideband processes may even cause an unexpected entanglement breakdown at high gain which can be observed both, in theory and in the experiment.

*This work was supported by French ANR-15-IDEX-02, EU-Horizon 2020(grant899561, MSC-754303 and MSCA-IF-835791) and by Deutsche Forschungsgemeinschaft through the Emmy Noether program (Grant No.ME4863/1-1).

Speaker: Sina Böhling (KIT, Karlsruhe)

4:00 PM Understanding jets of uniform helium droplets along their path of propagation

Helium droplets have a uniquely simple electronic structure, making them ideal targets for light-matter interaction studies. The recent development of intense X-ray pulses from free-electron lasers (FELs) and High-Harmonic Generation (HHG) sources has opened new ways to investigate individual helium nanodroplets with coherent diffraction imaging (CDI) [1,2]. From the diffraction patterns, the shapes of helium nanodroplets and embedded structures can be retrieved, and via time-resolved approaches, also laser induced dynamics can be investigated. Currently, efforts are leading towards imaging in the timescale of electron motion. For this, the generation of sub-femtosecond pulses with the help of short-wavelength FELs and high-intensity HHG sources is crucial. Due to the limited brightness of short light pulses, single-shot single-particle imaging becomes difficult. Nevertheless, we can aim at getting images with sufficient light signal by taking the average of repetitive diffraction patterns of identical droplets. This is where liquid jets of uniform and repetitive micrometer-sized helium droplets become very helpful [3].

We have shown via shadowgraphy imaging that liquid helium at about 3K, expanding through a micrometer sized nozzle at low stagnation pressures below 1 bar, can occasionally result in the formation of a straight stream of evenly sized and spaced helium droplets [3]. This extremely regular breakup translates in a stable target density at some distance from the nozzle, for example in the interaction region of an experiment, where the droplets can serve as an ideal target system. For the dominant, more irregular forms of jet breakup, we observed that the droplets grow and become more spherical as the distance from the nozzle increases. Especially interesting is the fact that the size distribution of these irregular droplet was found to be bimodal.

In this contribution, we investigate the propagation and evolution of helium droplets with computational simulations. We can explain the droplet growth with a coagulation process, induced by an initial longitudinal velocity distribution of the droplets. This initial velocity distribution is imprinted on the droplet jet from vibrations of the setup, which are especially strong when using a closed-cycle cryostat for cooling the helium. The experimentally found bimodal size structure can be reproduced by assuming an oscillatory motion of the nozzle generating the helium droplets. A new setup using a different, vibration-free flow cryostat, can eliminate these velocity oscillations, as is proved by the more mono-modal size-distribution. However, the previously observed, extremely regular breakup scenarios also seem to be less likely without strong vibrations of the nozzle. This observation hints us towards generating a controlled jet breakup by using a piezo transducer close to the nozzle, which forces a specific frequency onto the system.

[1] Gomez, L., Ferguson, K., Bryan, J. et al., Shapes and vorticities of superfluid helium nanodroplets. Science 345, 906-909 (2014).

[2] Rupp, D., Monserud, N., Langbehn, B. et al., Coherent diffractive imaging of single helium nanodroplets with a high harmonic generation source. Nat Commun 8, 493 (2017).

[3] Kolatzki, K., Schubert, M., Ulmer, A., Möller, T., Rupp, D. and Tanyag, R., Micrometer-sized droplets from liquid helium jets at low stagnation pressures, Physics of Fluids 34, 012002 (2022).

Speaker: Mrs Marie Louise Schubert (ETH Zurich)

4:00 PM Using Four-Wave Mixing in Thermal Vapours as a single photon source

Single photon sources are highly sought after because photons are excellent quantum information carriers, and are important for quantum communication and fundamental quantum optics. We use a ladder energy level system on the 5S$_{1/2}$-5P$_{3/2}$-5D$_{3/2}$ states of thermal $^{87}$Rb vapour to produce a heralded single photon source with a heralded auto-correlation value of $g^2(\tau = 0) = 0.22\pm 0.2$ which is non-classical. We also place the vapour in a 0.6 Tesla magnetic field to implement this scheme in the hyperfine Paschen-Back regime, where the transitions are separated by more that their linewidth, which allows for a cleaner system.

Speaker: Clare Higgins (Durham University)

4:00 PM Viscous Fingering Modelling via Phase Field Approach

The viscous fingering instability occurs when a more viscous fluid is displaced by a less
viscous one in a Hele-Shaw cell. Instabilities at the interface form a variety of complex patterns via
tip splitting. In this work, we adopt the phase field method coupling with Navier Stokes equations
via surface tension to investigate the influence of several force combinations, such as inertial,
surface tension, and viscous forces, on the flow behaviors in three dimensions.

Speaker: Shan Lyu (IAM, KIT)

5:45 PM Momentum-resolved hard X-ray photoemission

Photoelectron momentum microscopy is used to study the dispersion of electronic properties at the Fermi level, states of the valence band using photoelectron energy, momentum and spin analysis. We investigated crystalline samples of Mo and Ge on circular dichroism in the angular distribution (CDAD). The results were obtained on the P22 and P04 hard and soft X-ray lines at the PETRA-III synchrotron radiation source (DESY, Hamburg). P22 employs a diamond phase retarder at hv=6 keV, while P04 provides tunable circular polarized light between hv=250 and 2700 eV. All bands carry a strong CDAD signature, which reaches up to 80 %. The asymmetry shows a zero-line, when the photon beam coincides with a mirror plane of the crystal in the patterns at 0° and 90°. For arbitrary angles, for example 30° and 60° the symmetry is broken. The angular dependence complements earlier work on CDAD. Similar zero lines also appear in the XPD patterns of core levels, as exemplified for Ge 3p photoemission at hv = 6 keV.

Speaker: Dr Olena Tkach (Institute of Physics, Johannes Gutenberg University, 55128 Mainz, Germany)

4:00 PM → 5:00 PM Vortrag für Schülerinnen: Beschleunigerphysik - Prof. Dr. Anke-Susanne Müller, IBPT, KIT, Trägerin des Landesforschungspreis Baden-Württemberg 2022

Mit Teilchenbeschleunigern dem Code des Universums auf der Spur: Präzisionsinstrumente für Wissenschaft und Gesellschaft
von Prof. Dr. Anke-Susanne Müller, IBPT, KIT, Trägerin des Landesforschungspreis Baden-Württemberg 2022

Teilchenbeschleuniger sind faszinierende Instrumente der Wissenschaft. Viele Dinge können nur an und mit ihnen erforscht werden und viele Entdeckungen werden und wurden mit ihnen gemacht. Und auch unser Alltag sähe ohne sie ganz anders aus. Doch wie funktionieren sie? Und wie sehen die Teilchenbeschleuniger der Zukunft aus? Welche Hindernisse gilt es dabei zu überwinden? Dieser Vortrag bietet einen Blick hinter die Kulissen eines im wahrsten Sinne des Wortes hoch spannenden Forschungsgebietes am KIT und informiert, wie man Beschleunigerphysik studieren kann.

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6:00 PM → 7:30 PM Panel discussion: "Female physicists in leadership positions - pathways and challenges"

Title: Panel discussion: Female physicists in leadership positions - pathways and challenges

Abstract:

In this panel discussion, high-profile female physicists will give insights into their pathways to leadership positions in science and industry. They will describe what helped them to attain their current position and will discuss opportunities and challenges for female physicists. Moreover, they will share some of their personal experience and how they manage to combine a leadership position with private life.

Panelists are Cornelia Denz (PTB), Beate Heinemann (DESY), Johanna Kowol-Santen (DFG), Daniela Lange (SAP), and Christine Meyer (Bosch). The panel discussion will be moderated by Alexandra Hund (KIT).

6:00 PM Panel Discussion: Female physicists in leadership positions - pathways and challenges

In this panel discussion, high-profile female physicists will give insights into their pathways to leadership positions in science and industry. They will describe what helped them to attain their current position and will discuss opportunities and challenges for female physicists. Moreover, they will share some of their personal experience and how they manage to combine a leadership position with private life.

Panelists are Cornelia Denz (PTB), Beate Heinemann (DESY), Johanna Kowol-Santen (DFG), Daniela Lange (SAP), and Christine Meyer (Bosch). The panel discussion will be moderated by Alexandra Hund (KIT).

Speaker: Alexandra Hund (KIT)

8:00 PM → 11:00 PM Conference Dinner

• delicious food and amusing entertainment

Sunday, November 27

9:00 AM → 10:30 AM Physics Talks - Micro-/Nanophysics 1

9:00 AM On the interplay between strain and temperature in germanium microstructures

In the last decade, several activities have shown how the performance of Ge-based optoelectronic devices, often required to operate in a wide temperature range, critically depends on both their strain status and on the carrier population of nearly degenerate bands, which are non-trivial function of the temperature. In this work, we provide a systematic study on how the temperature dependent distribution of strain can impact the optical performance of semiconductor devices. To this aim, we have investigated strained Ge microstructures, considering the influence of mechanical and thermo-mechanical features on the optical properties, instrumental to develop a thorough guideline in the assessment and design of integrated light emitters. In particular, we consider Ge micropillars with Silicon nitride (SiN) stressor layer deposited on top. The mechanical deformation is described by means of 3D finite element calculations, evidencing the impact of the lattice temperature on the lattice distortion induced by the SiN stressor material. To this aim we include the surface and longitudinal strain variations, together with off-diagonal strain components. The numerical data describing the stressor-induced surface strain is compared with experimental results, obtained by means of µ-Raman spectroscopy. A theoretical multi-valley effective mass method, including also the contribution of thermal strain and the effect of the strain gradient, is shown to fully capture the experimental photoluminescence spectroscopy experiments (PL), giving a strong theoretical insight into the interpretation of the spectra lineshape which results to be influenced by the non-uniform strain field. The combination of theoretical and experimental results allowed us to disentagle thermo-mechanical effects from those related to a temperature induced variation of the carrier distribution, a critical aspect for optoelectronic devices operating in a wide temperature range. In perspective, our comprehensive approach can be applied to the design and characterization of strain-based electronic and opto-electronic devices, providing a quantitative description of the temperature-dependent strain relaxation mechanism thus elucidating how heating can impact the optical performance.

Speaker: Costanza Manganelli (IHP – Leibniz-Institut für innovative Mikroelektronik)

Manganelli_women_in_phys.pdf

9:15 AM Segregation to creep-induced planar faults in Ni-base SX superalloys

Ni-base single-crystal (SX) superalloys find application in turbine blades for gas engines due to the high-
temperature and high-stress strength originating from the coherent γ/γ’ microstructure. It is well-known
at sufficiently high stresses, two 1/2<101> dislocation families with different Burgers vector can react
and dissociate into two partial dislocations in γ channels. This allows the leading 1/3[-1-12] Shockley
partial dislocation continuously gliding on {111} planes to cut into γ’ precipitates where they create
planar faults [1]. We study the segregation behaviours of alloying elements across the planar faults by
performing the [11-2] (111) creep shear experiments, to intentionally activate the slip system [11-2]
(111) with the highest Schmid factor of 1 where the resolved shear stress is exactly equal to loading
stress. The creep-deformed specimens are interrupted after 1% and 2% shear strain under 250 MPa at
750 °C. The resulting microstructure is investigated using conventional transmission electron
microscopy (TEM), analytical scanning TEM (STEM) with energy-dispersive X-ray spectroscopy (EDXS)
focussing on structural, physical, and chemical details of the local deformation.
We investigated the specimen perpendicular to the (111) plane with the [1-10] direction parallel to the
electron beam. Numerous stacking faults (SF) are observed after 1% and 2% creep strains. Fringe
contrasts under two-beam conditions indicate inclined stacking faults, where the 2% strain sample has
more planar faults within one γ’ precipitate indicating a higher density of planar faults in the 2% sample.
High-resolution STEM micrographs illustrate the superlattice extrinsic nature of stacking faults (SESF) in
the 1% and 2% strained samples. The chemical distributions across SESF are measured by EDXS and the
corresponding concentration profile of 1% and 2% samples. Both samples show almost similar
segregation tendency, which is that γ forming elements Cr, Co and Re are enriched across the SESF while
γ’ alloying elements Ni and Al are depleted, which is partly in agreement with theoretical predictions [2].
For these measurements all microscope parameters and sample thickness for EDXS analysis are kept
the same to quantitatively find out how creep strain and time affect the evolution of segregation.

Speaker: Zhongmin Long (LEM, KIT)

2022-11-26_ Female physicist Conference_Zhongmin Long.pdf

2022-11-26_ Female physicist Conference_Zhongmin Long.pptx

9:30 AM Exploring dislocation networks for continuum modeling

The striving for advanced materials with well-defined microstructures has led to an increasing effort towards a physically based description of the motion of dislocations as the cause of plastic deformation. Several dislocation-based continuum theories have been introduced, but only recently rigorous techniques have been developed for performing meaningful averages over systems of moving, curved dislocations and their interactions, yielding evolution equations based on dislocation density. Regarding a self-consistent coarsening of dislocation microstructures in order to construct an efficient numerical implementation, several issues have to be solved including calculation of the internal stress field of a system of dislocations, dislocation nucleation and interaction, as well as boundary conditions for internal interfaces. The understanding and development of predictive modelling techniques to capture the plastic flow and hardening behaviour of a material in a physically based formulation is a central aspect for the design of new materials and the optimization of microstructures.
In this presentation, we discuss the challenges as well as the potential of a dislocation based continuum theory of plasticity. We present and analyse homogenization techniques to represent the formation and evolution of dislocation microstructures including dislocation interaction and multiplication. The introduced formulations are discussed in the context of work hardening mechanisms in the stage II regime in face-centered cubic crystalline materials. The relevance of an interplay of dislocations between slip systems for dislocation multiplication mechanisms and dislocation reactions leading to work hardening is presented in comparison with discrete dislocation dynamics simulations as well as experimental investigations.

Speaker: Prof. Katrin Schulz (Karlsruhe Institut für Technologie / Hochschule Karlsruhe)

2022_DPT_KatrinSchulz.pdf

9:45 AM Attainments and Challenges of High Temperature Oxidation Resistance of Refractory High Entropy Alloys: Literature Review and Own Results

Refractory High Entropy Alloys (RHEA) are considered novel promising high temperature materials for structural applications at ultra-high temperatures primarily due to their attractive mechanical properties. While many RHEA suffer from poor oxidation resistance similar to that of pure refractory metals, some RHEA exhibit very good protectiveness which is attributed to the formation of either well-known protective scales such as α-Al2O3, or rarely encountered complex oxides such as CrTa-based oxides. In this contribution, the currently available literature on high temperature oxidation behavior of RHEA is reviewed with respect to the oxidation kinetics as well as oxide scale growth and constitution. In addition, own results on the formation and growth of complex CrTa-based oxides, which exhibit high thermodynamic stability and slow growth kinetics, are presented.

Speaker: Bronislava Gorr (KIT)

9:00 AM → 10:30 AM Physics Talks - Particle Physics Experiment

9:00 AM Layout of the Interaction Region for Electron Proton Collisions in the LHeC and the FCC-eh Collider

The LHeC and the FCC-eh projects study the design of future deep inelastic electron-proton colliders at CERN. In the LHeC, collisions between electrons and protons in the LHC interaction region IR2 will be established in parallel to the standard LHC operation: The e-p collisions will take place simultaneously with the experiments ATLAS, CMS and LHCb, while alternating with the ALICE experiment in IR2.
The electrons will be accelerated to a kinetic energy of $50$ GeV in an energy recovery linear accelerator (ERL) positioned tangentially to the LHC and brought into collision with one of the $7$ TeV proton beams of the LHC. The second proton beam of the LHC is guided through the interaction region with a minimal distance of $10 \sigma$ to the colliding beams. The design luminosity of the LHeC of the order of $10^{33} \mbox{cm} ^{-2} \mbox{s}^{-1}$ sets special requirements for the optics of the three beams, as the two proton beams of the LHC, as well as the electron beam will pass through a common interaction region.
First design studies of the optics and orbits of the three beam scenario in the LHeC have been performed to define the apertures and gradients of the required magnets. Different magnetic settings have been studied to establish a highly asymmetric beam optics for the colliding and non-colliding proton-beam in the LHeC in order to achieve the highest luminosity and machine performance and minimise the beam-beam interaction. The studied LHeC design will later be applied to the FCC-eh design, where an ERL is placed tangentially to the FCC, enabling collisions of $60$ GeV electrons with $20$ TeV protons.

Speaker: Ms Tiziana von Witzleben (CERN)

Layout_LHeC.pdf

9:15 AM Timing for pileup mitigation at the CMS detector at HL-LHC

The LHC will be upgraded to a collider with 10 times higher luminosity, the high luminosity (HL)-LHC. One main challenge arising from the upcoming high luminosity, is the large amount of interactions that occur in one proton-proton bunch crossing, and therefore the separation of the interaction of interest from the additional ones (pileup). The insertion of a new timing layer in the upgraded CMS experiment is planned, to use timing as an additional discrimination variable between signal and pileup.
One interesting channel to probe at the HL-LHC is vector boson fusion (VBF) Higgs pair production that has two characteristic jets in the forward region of the detector. The separation of this signal from pileup is extremely challenging. In this study, we present the performance of using timing information for pileup per particle identification (PUPPI).

Speaker: Anna Albrecht (Universität Hamburg)

Timing_for_PUPPI.pdf

9:30 AM The LHCb Upgrade Vertex Locator

The LHCb experiment at the Large Hadron Collider at CERN for the reconstruction of hadrons containing $b$ and $c$ quarks produced in proton-proton interactions. Run III of the LHC, which has started earlier this year, will see an increase in collision rates at LHCb by a factor of about five compared to previous runs in the last decade, necessitating a complete redesign of the experiment including a full detector readout at $30\ \text{MHz}$.

The Vertex Locator (VELO) is the closest sub-detector to the proton beam and surrounds the proton-proton collision region in order to track charged particles produced in the interaction and reconstruct production and decay vertices. It has been upgraded to a silicon pixel detector with many innovative components. The number of modules has been increased to 52 instead of 42 with its distance from the beam in the closed position at $5.1 \text{mm}$, around $3 \text{mm}$ closer than its predecessor. Each module contains 4 sensors, each bump-bonded to 3 VeloPix ASICs capable of reading out at the required rate. The ASICs are cooled by evaporative CO$_2$ through microchannels in thin plates of silicon substrate directly underneath the chips to maintain a temperature of $-20^\circ\text{C}$. The VELO is currently undergoing commissioning, vital for calibrating and understanding this new detector.

Speaker: Tamaki Holly McGrath (The University of Manchester)

VELO_talk_at_KIT.pdf

VELO_talk_at_KIT.pptx

9:45 AM GNN-based Track and Vertex Finding at Belle II

In many new physics extensions of the Standard Model, new mediator particles may decay into a pair of charged particles leaving a unique signature of a displaced vertex and charged tracks. These displaced decay products are an important signature in searches for dark sectors in collider experiments.
The current Belle II trigger algorithm is not designed for events with displaced vertices and therefore insufficient to detect these events. Traditional tracking algorithms such as Legendre transformation and Combinatorial Kalman Filter scale poorly with the high beam-background, which is expected to increase significantly in the upcoming data-taking of the Belle II experiment.
Therefore, we develop a Graph Neural Network (GNN) based approach to find particle tracks and displaced vertices in the Central Drift Chamber of Belle II, where we can realize track measurements using a graph representation of detector hits.

Our GNN-based track and vertex finding is split in a pipeline to enable FPGA implementation for real-time reconstruction, The first step consists of building the graph out of the detector measurements. Next a GNN model is applied to classify the edges of the previously built graph to filter out beam-background. Finally, additional machine learning methods will be added to find all particle tracks and the displaced vertices.
This work introduces our approach and focuses on the graph building aspect as well as introducing the model evaluation for edge classification.

Speaker: Lea Reuter

DPT_GNNTrackingBelleII_LReuter.pdf

10:00 AM Substructure tagging with mass and pt dependent variable-R jet clustering and a soft drop veto

The Heavy Object Tagger with Variable R (HOTVR) is an algorithm for the clustering and identification of boosted, hadronically decaying, heavy particles. The central feature of the HOTVR algorithm is a vetoed jet clustering with variable distance parameter R, that decreases with increasing transverse momentum of the jet. In this talk, we present improvements to the HOTVR algorithm, replacing the mass jump with a soft drop veto in the clustering. We study the performance of jet substructure tagging with HOTVR and ungroomed variable R jets, where we use machine learning techniques and energy flow polynomials to analyse the information loss from the soft drop veto. In addition, we show preliminary results of a distance parameter that changes with the jet mass and the transverse momentum, allowing to achieve an optimal value of R for W, Z, H bosons and top quarks simultaneously.

Speaker: Dr Anna Benecke (UC Louvain)

20221127_HOTVR_AnnaBenecke.pdf

9:00 AM → 10:30 AM Physics and Profession 4

9:00 AM My path from physics to climate action

In this talk I would like to give you insights into my job at the German climate NGO atmosfair and my career at the cross-section of energy, development and climate action. I hold a BSc in Physics from the University of Konstanz and an MSc in Sustainable Energy Engineering from NTNU in Trondheim and DTU in Copenhagen. After finishing my degree, I worked as a Trainee at the European Commission in the General Directorate for Research and Innovation. Since 2019, I am working as a project developer for climate change mitigation projects at atmosfair. My day-to-day job involves identifying new project opportunities, designing impact monitoring schemes, analysing project data, negotiating collaboration agreements and much more. In my career I have had the opportunity to work with numerous partners to support the energy transition in different African countries, including the uptake of modern electric cooking for households. My physics degree allowed me to do my job because it equipped me with technical understanding and skills, perseverance and the flexibility to choose my individual professional path.

Speaker: Annika Richter

My path from physics to climate action_Annika Richter.pdf

9:30 AM Eine Ente im Ministerium

„Was willst Du später mal werden, wenn Du groß bist?“ „Lehrerin!“ „Schriftstellerin!“ „Astronautin!“ Manche Berufswünsche hört man hingegen von Kindern selten. Besonders, wenn sie im Umfeld ziemlich unbekannt sind: Wissenschaftsmanagerin. Referentin. Physikerin.
1986 geboren, gehört Dominique Sauer zu den „Millenials“. Diese krisengeschüttelte Generation zeichnet sich unter anderem dadurch aus, dass sie sich sehr gerne Optionen offenhält[1]. Dominiques Physikstudium sollte auch eben diesen Zweck erfüllen: ihr möglichst viele Türen offenhalten. Nur waren es letzten Endes ganz andere Türen als erwartet, die sich tatsächlich öffneten. Ihr Weg führte sie vom Studium an der Technischen Universität Darmstadt ins Wissenschaftsmanagement am Karlsruher Institut für Technologie, dann wieder in die Forschung zurück und schließlich als Referentin ins Bundesministerium für Bildung und Forschung.
In ihrem Vortrag möchte sie euch ein Stück ihres bisherigen Weges mitnehmen und Einblicke geben, wie sich Physiker:innen im Wissenschaftsmanagement und in einer Bundesbehörde so schlagen: was hilfreich dafür ist, was die Tätigkeiten mit sich bringen und natürlich: was das alles mit Enten zu tun hat.
[1] https://de.wikipedia.org/wiki/Generation_Y, abgerufen: 07.10.2022

Speaker: Dominique Sauer (BMBF)

10:00 AM Patent Attorney Life as a Physicist

I will give a glimpse into the training and work life as a German and European patent attorney. After spending nearly 20 years training and working on temporary jobs in academia as a string theorist, in 2018 I decided to change my career path and started my by now completed training as both German and European patent attorney in a small patent law firm. To become a patent attorney, you need a M.Sc. (or equivalent) in a scientific or technological field and then train for at least three more years before completing a set of exams on patents, trademarks, designs and general legal questions such as inventors' rights. In daily life, you talk to inventors, discuss their ideas with them and translate the ideas into a legal language. You help with filing patent applications and the procedural steps to get a patent granted. You also help with protecting your client's interests against competitors. Being a physicist with international experience is ideal for becoming a patent attorney as we are trained on independent thinking and problem solution on a wide variety of topics, and the international patent sector operates to a large extent in English, with Germany being the largest single European patent market/country.

Speaker: Prof. als Jun.-Prof. a.D. Dr. Gabriele Honecker (Patent Attorney)

Honecker_PatentAttorneyLife_Physikerinnentagung_27Nov2022.pdf

9:00 AM → 10:30 AM Workshop 5: "Sagen Sie mir, was ich verdienen soll - mein Wert fürs Unternehmen": Morning

Trainer: Karin Doderer

Zielsetzung des Workshops ist es, Impulse zu geben zur Reflexion zum Thema Gehaltsverhandlung und zur Darstellung des eigenen Mehrwerts für den zukünftigen Arbeitgeber.
Mögliche Inhalte/Themenschwerpunkte des Workshops können sein:

• Was ist mein Produkt = mein Alleinstellungsmerkmal bzw. Mehrwert für das Unternehmen? (Eigene Stärken bewusst machen und kompetenzbasiert beschreiben.)

• Was bin ich wert? (Welche Haltung habe ich zum Thema Geld + Gehalt? Welche selbst gebauten Stolperfallen, z. B. Glaubenssätze hindern mich daran, angemessene Forderungen zu stellen?)

• Wie mache ich meinem zukünftigen Arbeitgeber meinen Mehrwert bewusst? (Das eigene Maß für den souveränen Auftritt finden; Bedeutung von nonverbaler Kommunikation (Kleidung, Raumgestaltung, Blickkontakt))

• Welche Rolle spielen Geschlechterstereotype, Geschlechterrollen und Rollenerwartungen bei diesem Thema?

Target groups: female MA students, female PhD candidates and female postdocs who consider a change into industry

9:00 AM → 10:30 AM Workshop 6 (online): "Salary negotiations training": Morning

This workshop will take place exclusively online via zoom!

Trainer: Tina Groll

Description: The workshop is aimed at interested female master's students as well as female PhD candidates and female PhD physicists who are considering a change into industry. Here, participants learn what starting salaries are common by specialty and sector, how to determine their market value, what to pay attention to in applications and salary interviews, and what else is important.

Target groups: female MA students, female PhD candidates and female postdocs who consider a change into industry

10:30 AM → 11:00 AM Coffee break

11:00 AM → 12:30 PM Physics Talks - Micro-/Nanophysics 2

11:15 AM Towards atom diffraction through graphene

In recent years, the introduction of large momentum transfer beam splitters to matter-wave interference experiments led to an increase in the sensitivity of a given interferometric measurement [1,2]. For nanomechanical gratings this corresponds to a reduction of the grating period. However, the stability and fabrication precision of those gratings limit the minimal grating period possible. To overcome this limitation the use of the crystalline structure of single-layer graphene as the grating is proposed, achieving a lattice period of 246 pm [3]. This will allow the study of atom-graphene interactions in an unprecedented regime. Among others, the time-resolved study of modifications of graphene membranes by introducing foreign atoms or defects will be possible, as well as investigating of couplings to the electronic structure of graphene in detail. The experimental set-up, current status of the experiment, and scientific goals will be presented in this contribution.

[1] R. Parker, C. Yu, et al., Science 360, 191 (2018)
[2] M. Gebbe, J.-N. Siemß, et al. Nat. Commun. 12, 2544 (2021)
[3] C. Brand, M. Debiossac, et al., New J. Phys. 21, 033004 (2019)

Speaker: Carina Kanitz (Deutsches Zentrum für Luft- und Raumfahrt)

Towards atom diffraction through graphene.pdf

11:30 AM Hydrogenation of Pd nanoparticles at the nanoscale with in-situ TEM

Palladium is an ideal model system to study hydrogen absorption in metals due to its extreme affinity to hydrogen, high solubility up to H/Pd = 1 atomic ratio, fast hydrogen absorption and desorption at room temperature and simple phase diagram. Pd nanoparticles can be used in catalysis and assist in hydrogen delivery into other materials for hydrogen storage through a spill-over process. Nanoscale systems reveal significant thermodynamic deviations from the bulk due to higher surface to volume ratio, absence of grain boundaries, different behavior of defects and mechanical stress.
In this work, we investigate the behavior of Pd nanoparticles and formation of PdHx in real time with in-situ H2-gas TEM. With the special gas holder from Protochips it is possible to reach pressures up to 1 atmosphere and study the particles at elevated temperatures within the stability limit of the nanoparticles up to 200°C. In this work, we can observe initial stages of hydrogen absorption in Pd nanoparticles, the local phase change at different temperatures and pressures with the help of spectroscopic and diffraction techniques at the nanoscale.

Speaker: Svetlana Korneychuk

11:45 AM Polymer to Carbon Transition: In Situ Pyrolysis of 3D Printed Microstructures

Carbon has been well known as a compelling material to compete with silicon in the field of microchips.
One promising method to fabricate micro- or nanoscale carbon architectures is to pyrolyze a pre-
patterned polymer precursor [1]. Pyrolysis is, therefore, a crucial processing parameter. However, a
mechanistic understanding of the pyrolysis process for sub-micrometer polymer geometries is still
missing. In particular, for the temperature regime, where the highest mass loss and, in turn, the highest
shrinkage is observed, a detailed analysis of the pyrolysis-induced shrinkage kinetics, geometry
dependence shape deformation, and the roles of atmosphere and surface area is still lacking [2].
In this work, we aim to fill this knowledge gap and provide a comprehensive understanding of
morphological deformation upon pyrolysis. Here, we report a systematic study of in situ pyrolysis
process by varying environment pressure, heating temperature, and sample geometry (surface-to-
volume ratio) in an environmental SEM (ESEM). We use direct laser writing of IP-Dip photoresist to
print microstructures directly on MEMS heating chips [3]. We focus on the early stage of carbonization
from 450 to 550 °C, where polymer precursor experiences the greatest mass loss and structural
shrinkage. The structural changes are directly tracked by secondary electron imaging.
We reveal the pyrolysis kinetics illustrating the temporal and temperature dependency of the
deformation. When evaluating the data pool by generating model-free master curves, we fully
describe the dynamic process and extract the effective activation energy (Ea). After changing the
environmental conditions, the shrinkage behavior turns out to be fundamentally different, largely
kinetically hindered. A prevalence of the aspect ratio on kinetics and the final size becomes apparent,
causing a dramatically lower Ea.
To complete the picture of the structural changes during pyrolysis-induced transformation, our
ongoing experiments tackle focused ion beam (FIB) micromachined cross sections of the microstruts
after isothermal exposure using scanning transmission electron microscopy (STEM). Not only
morphological changes can be characterized but also local structural and chemical information by
electron energy loss spectroscopy in 4D-spectrum images (EELS-SI).
In conclusion, our in situ and scale-bridging study paves the way to a thorough understanding of
morphological mechanisms upon pyrolysis and correlated property strengthening. The precise tuning
of functional metamaterials by pyrolysis will facilitate the development of industrially relevant carbon
device fabrication.

Speaker: Qing Sun (MNM, LEM KIT)

DPT_Micro-Nanophysics 2_in situ pyrolysis_QS.pptx

12:00 PM Structure and reactivity of negatively charged platinum and palladium clusters

Small Pt- and Pd-clusters play an important role as active sites in heterogeneous catalysis. For this reason, we are interested in their gas phase structure. Here we show the results of a joined experimental and theoretical study. Experimentally, structural information is obtained in the group of Schooss by trapped ion electron diffraction (TIED). The resulting scattering function is compared to theoretical counterparts that were obtained by structure optimization of guess structures with density functional theory.
Here, results for three different systems are presented:
For Pt$_n^-$-clusters with $n$ in the range from 6 to 13, guess structures were obtained by the use of genetic algorithms with empirical potentials and based on density functional theory. The set of structures was extended by literature data. By combining theory and experiment it was possible to assign the structures observed in the experiment [1].
For Pd$_n^-$-clusters with 55 to 147 atoms, the transition from icosahedral motifs to bulk like fcc-structures [2] is considered.
Finally, we performed quantum chemical calculation to investigate the reactivity of selected truncated octahedral Pt$_n$-clusters with oxygen [3].
[1] Bumüller, D.; Yohannes, A. G.; Kohaut, S.; Kondov, I.; Kappes, M. M.; Fink, K.; Schooss, D. J. Phys. Chem. A 2022, 126, 3502 doi:10.1021/acs.jpca.2c02142
[2] Kohaut, S.; Rapps, T.; Fink, K.; Schooss, D. J. Phys. Chem. A 2019, 123, 10940 doi:10.1021/acs.jpca.2c02142
[3] Yohannes, A. G.; Fink, K.; Kondov, I. Nanoscale Adv. 2022 doi:10.1039/d2na00490a

Speaker: Prof. Karin Fink (Karlsruher Institut für Technologie)

Fink-Karin.pdf

11:00 AM → 12:30 PM Physics Talks - Particle Physics Theory

11:00 AM Numerical Investigation of Isospin Breaking Effects in 1+1D QED

We study the automatic fine-tuning of isospin breaking effects by conformal coalescence found by Howard Georgi in the 2-flavor Schwinger model, i.e. 1+1D QED. Numerical investigation of pion mass splitting on a 1+1 dimensional lattice confirms that the symmetry breaking effects are exponentially suppressed in the fermion mass $m_f$ even for large splittings of $\delta m \approx m_f$. Some results of this work are shown and a brief introduction to lattice field theory is given.

Speaker: Nuha Chreim (Bergische Universität Wuppertal)

DPT_Talk_Nuha_Chreim.pdf

11:15 AM Non-thermal particle production after first-order phase transitions: what happens after bubbles collide?

In a cosmological first-order phase transition, bubbles of true vacuum nucleate and expand due to the difference in vacuum energy. We study non-thermal particle production from the collisions of such bubbles, which can be relevant for many beyond the Standard Model scenarios, such as baryogenesis and dark matter. The bubble collisions result in local excitations of the background scalar field, producing scalar waves, which can decay into particles that are coupled to the scalar field. We discuss various important aspects of this process, highlighting crucial differences compared to particle production from oscillating scalar fields in preheating/reheating scenarios.

Speaker: Henda Mansour (University of Hamburg)

dpt22_HendaMansour.pdf

11:30 AM Strong first-order electroweak phase transition in selected extended scalar sector models

To explain the observed baryon asymmetry of the universe (BAU) in an electroweak baryogenesis (EWBG) scenario, beyond the standard model (BSM) models are required to fulfill the necessary Sakharov conditions, i.e. they need to provide sufficient departure from thermal equilibrium by enabling a strong first-order electroweak phase transition (SFOEWPT), as well as provide a source of additional CP violation.
Using the C++ code BSMPT, we investigate the allowed parameter space of BSM models for providing an SFOEWPT by minimizing the one-loop daisy-resummed finite temperature effective potential and taking into account all relevant theoretical and experimental constraints.
This talk focuses on two recent directions of our work: First, the study of the interplay between an SFOEWPT and Higgs pair production in a 2HDM-EFT. Second, the promising model ‘CP in the Dark’ which provides a dark sector with a dark matter (DM) candidate and additional explicit CP violation in the dark sector. For ‘CP in the Dark’, we find valid SFOEWPT points that offer additional spontaneous CP violation at finite temperature and lie within the reach of XENON1T and future invisible Higgs decay searches for DM.

Speaker: Lisa Biermann (Institute for Theoretical Physics, Karlsruhe Institute of Technology)

DPT22_LBiermann.pdf

11:45 AM GW waves and the triple Higgs boson coupling in the 2HDM

Many popular extensions of the SM require sizeable modifications to the trilinear Higgs boson coupling in order to accommodate a first-order electroweak (EW) phase transition. Cosmological first-order phase transitions can give rise to a primordial gravitational wave (GW) background which could be observable at future space-based GW detectors such as LISA. Focusing on the Yukawa type-II 2HDM and taking into account various theoretical and experimental constraints in combination with the condition of the presence of a first-order EW phase transition, we scrutinize the relevant parameter space regions and verify whether these regions could be probed in a complementary way at the HL-LHC via nonresonant Higgs boson pair production and at the LISA experiment via the possible observation of a GW signal. We find regions of the parameter space that give rise to GW signals that might be detectable at LISA, and these regions predict values of the triple Higgs boson couplings that are potentially observable at the HL-LHC or other future colliders. The measurements of Higgs boson pair production will therefore provide important constraints on the possiblity of observing GW signals at LISA.

Speaker: María Olalla Olea Romacho (DESY)

Olea_DPT22.pdf

12:00 PM Higgs pair production at the HL-LHC in the 2HDM: insight into trilinear Higgs couplings

The Standard Model (SM) of particle physics predicts a minimal Higgs
sector and the existence of one Higgs boson that has already been
discovered at the Large Hadron Collider (LHC). However, nothing
prevents nature from having a non minimal Higgs sector. In
particular, when a set of theoretical and experimental constraints
are taken into account, it is possible to postulate theories beyond
the SM that aim at solving some of its shortcomings. One simple
example is the 2 Higgs Doublet Model (2HDM), which predicts a total
of ve Higgs bosons.
In this context, trilinear Higgs self coupling is an important
parameter to properly characterize the Higgs potential and determine
the Higgs sector that is realized in nature. Moreover, the loose
experimental constraints on it available so far allow for a
reasonable deviation from the SM expectation. Access to this
parameter can be provided by Higgs pair production processes. The
small cross section of this process requires higher luminosity
prospected at further runs of the LHC. Focusing on the High
Luminosity LHC, we evaluate several observables in the framework of
the 2HDM, namely, the total di-Higgs production cross section and
the differential cross section distributions with respect to the
invariant mass of two SM-like Higgses in the nal state. We explore
dierent scenarios that were obtained to maximize the trilinear Higgs
couplings and evaluate whether the corresponding eect on the
aforementioned observables can be determined with sucient
signicance. We furthermore analyze the eect of the contribution of
the resonant diagram involving a heavy CP even Higgs exchange, its
mass and total decay width. Finally, we point out the experimental
challenges of setting an appropriate bin location and size for
extracting these features of the model out of the invariant mass
distributions.

Speaker: Kateryna Radchenko

Radchenko_DPT22.pdf

12:15 PM $q_T$-resummation for Higgs production via quark annihilation

In order to exploit the full potential of the high-precision measurements at LHC new theory predictions are needed. The Higgs boson plays an important role not only in the Standard Model (SM) but also in various BSM models. Thus, precise predictions of its kinematic distributions and of its decay products are crucial to be sensitive to possible deviations from the SM.
Unfortunately, in the kinematic region where most Higgs bosons are produced, the perturbative corrections are largest, which can even lead to a complete breakdown of the perturbative expansion. To avoid this the dominant contributions can be resummed to all orders in perturbation theory. This allows to make precise predictions for kinematic distributions even in this troublesome but important kinematic region.
In my talk, I will give a short introduction to $q_T$-resummation in soft-collinear effective field theory (SCET) and present a new prediction for Higgs production via quark annihilation where these perturbative corrections are resummed to N$^3$LL + N$^3$LO accuracy.

Speaker: Rebecca von Kuk (DESY)

dpt2022.pdf

11:00 AM → 12:30 PM Physics and Profession 5

11:00 AM Working as a physicist at the German Research Foundation

In my talk I would like to give you insights into my job at the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), the central self-governing research funding organisation in Germany. With those insights in my day-to-day job I will also give you a short overview of the tasks of DFG and the funding portfolio as well as how the assessment and decision process works. After graduation (Diploma) at the University of Cologne University in 1994, I worked as scientific assistant at the Department for Geophysics with atmospheric science in the focus of my interests, earning my PhD in 1998 within the European project TOASTE-C (Transport of Ozone and Stratosphere Troposphere Exchange). Crossing the border between atmospheric physics and chemistry, I spent several years as postdoc at CNRS (Centre National de la Recherche Scientifique, Service d’Aéronomie) in Paris. Leaving active research, I assumed in 2002 the position of a Programme Officer at DFG Head Office in Bonn, taking over the responsibility as Programme Director for Condensed Matter Physics and Atmospheric Science in 2005. From 2008 I was heading the Division of Chemistry and Process Engineering, in 2019 I took over the responsibility as Head of Division for Physics and Chemistry, since 2015 I am also Deputy Head of the Department Scientific Affairs.

Speaker: Johanna Kowol-Santen (DFG, German Research Foundation)

Präsentation_dpt2022_DFG.pdf

11:30 AM From physicist to IT executive – a path of many new beginnings

In this talk I would like to give you insights into my job at SAP and into live events and inspirations that took me onto this path. I started my career as physics student at KIT, where I finished my Diplom in 1996. I also hold a PhD in physics from Clarkson University New York in collaboration with University of Connecticut and McGill University in Montreal. I recently complemented my physics and IT background with an Executive MBA from Mannheim Business School.
I started at SAP as a software engineer, followed by multiple roles, living in India and US. Now, 20 years later, I am leading the product organization for our Payroll, Time Management, Compensation and Benefits products – a team of 40 different nationalities across the globe. I am also executive sponsor for a product initiative called “Business Beyond Bias”, which aims at leveraging HR technology and machine learning to detect and prevent unconscious bias in HR decision making processes.
Finally, I would like to share my experience with you regarding women in leadership positions and juggling children and career.

Speaker: Daniela Lange (SAP)

Daniela Lange_DPT_KIT_CP.pdf

12:00 PM Angewandte Geophysik - ein modernes Werkzeug zur Vorerkundung im Bauwesen

Während sich die Allgemeine Geophysik mit dem physikalischen Aufbau des Erdkörpers beschäftigt, konzentriert sich die Angewandte Geophysik auf die Untersuchung der oberen Erdkruste mit verschiedensten Aufgabenstellungen in Bereichen Energie, Rohstoffe und Umwelt.
Insbesondere im Bereich des Bauwesens spielt die Geophysik eine immer größere Rolle. Denn hier werden die indirekten Verfahren zerstörungsfrei von der Oberfläche aus, ohne direkten Eingriff in die Substanz, großräumig zur Vorerkundung des Untergrundes eingesetzt und erhält dabei Informationen über Aufbau, Struktur und Zustand des Untergrundes durch die Interpretation physikalischer Messwerte.
Das Ziel des Vortrags wird die Vermittlung einer realistischen, praxisnahen Vorstellung der Einsetzbarkeit geophysikalischer Methoden anhand ausgewählter Fallbeispiele sein.

Speaker: Nicole Kuntz (GGU)

Vortrag_PT-KU.pdf

11:00 AM → 12:30 PM Workshop 5: "Sagen Sie mir, was ich verdienen soll - mein Wert fürs Unternehmen": Noon

Trainer: Karin Doderer

Zielsetzung des Workshops ist es, Impulse zu geben zur Reflexion zum Thema Gehaltsverhandlung und zur Darstellung des eigenen Mehrwerts für den zukünftigen Arbeitgeber.
Mögliche Inhalte/Themenschwerpunkte des Workshops können sein:

• Was ist mein Produkt = mein Alleinstellungsmerkmal bzw. Mehrwert für das Unternehmen? (Eigene Stärken bewusst machen und kompetenzbasiert beschreiben.)

• Was bin ich wert? (Welche Haltung habe ich zum Thema Geld + Gehalt? Welche selbst gebauten Stolperfallen, z. B. Glaubenssätze hindern mich daran, angemessene Forderungen zu stellen?)

• Wie mache ich meinem zukünftigen Arbeitgeber meinen Mehrwert bewusst? (Das eigene Maß für den souveränen Auftritt finden; Bedeutung von nonverbaler Kommunikation (Kleidung, Raumgestaltung, Blickkontakt))

• Welche Rolle spielen Geschlechterstereotype, Geschlechterrollen und Rollenerwartungen bei diesem Thema?

Target groups: female MA students, female PhD candidates and female postdocs who consider a change into industry

11:00 AM → 12:30 PM Workshop 6 (online): "Salary negotiations training": Noon

This workshop will take place exclusively online via zoom!

Trainer: Tina Groll

Description: The workshop is aimed at interested female master's students as well as female PhD candidates and female PhD physicists who are considering a change into industry. Here, participants learn what starting salaries are common by specialty and sector, how to determine their market value, what to pay attention to in applications and salary interviews, and what else is important.

Target groups: female MA students, female PhD candidates and female postdocs who consider a change into industry

12:30 PM → 2:00 PM Lunch break

2:00 PM → 2:45 PM Keynote Physics Talks 5: Particle Physics Theory - Prof. Ramona Gröber, University of Padova

Keynote

2:00 PM Quo vadis, Higgs boson?

The Higgs boson has recently celebrated the 10th birthday of its discovery. In the meanwhile, we have learned a lot about its properties, but there is still much more to be learned...
In this talk, I will give an overview of what we already know about it and what there is still to be understood. Furthermore, I will discuss the implications to the unanswered questions of the Standard Model of particle physics.

Speaker: Ramona Groeber (Università di Padova and INFN, Sezione di Padova)

DPT_rgroeber.pdf

2:00 PM → 2:45 PM Keynote Physics Talks 6: Microstructure of Materials and Systems - Prof. Erica Lilleodden, Fraunhofer-Institut für Mikrostruktur von Werkstoffen und Systemen IMWS

Keynote

2:00 PM On the self-similarity of structural evolution of nanoporous gold

This talk addresses the validity of the commonly assumed self-similarity of the structural evolution of nanoporous gold. To this extent, a quantitative study of the salient structural parameters identified from so-called ‘representative volumes’ of the bicontinuous nanoporous gold (NPG) network has been carried out and is based on a variety of characterization approaches. 3D-focused ion beam tomography applied to as-dealloyed and isothermally annealed NPG samples provide direct assessment of topological characteristics, while TEM identifies the evolution of defect distributions. After identifying sufficiently large representative volumes, we show that the ligament width distributions coarsen in a sufficiently self-similar, time-invariant manner, while the scaled connectivity density shows a self-similar ligament network topology. Using these critical parameters, namely mean ligament diameter and connectivity density, the Gibson–Ashby scaling laws for the mechanical response of cellular materials are revisited. The inappropriateness of directly applying the Gibson– Ashby model to NPG is demonstrated by comparing finite element method compression simulations of both the NPG reconstruction and that of the Gibson–Ashby solid model; rather than the solid volume fraction, we show that an effective load-bearing ring structure governs elastic behaviour. On the other hand, TEM investigations show a breakdown in self similarity of internal microstructure of the ligaments themselves, and may explain some of the variations in the mechanical behavior in the plastic regime. The consequences of the results will be placed the context of tailoring nanoporous metals for targeted applications.

Speaker: Erica Lilleodden (IMWS, Halle)

2:45 PM → 3:30 PM Keynote Physics Talks 5: Particle Physics Experiment - Prof. Monica Dunford, University of Heidelberg

Keynote

2:45 PM Beyond particles - What the Higgs boson tells us about the universe

The discovery of the Higgs boson in 2012 completed the particle content of the Standard Model of particle physics. This particle, however, is the only scalar particle we know of and through its unique properties and interactions it plays a critical role in the evolution of our universe. In this talk, I will discuss how the tiniest of particles can affect the development of some of the biggest structures of our universe. I will highlight how the Higgs boson interacts with other particles as well as with itself and how this self-interaction may be the critical aspect to explaining the matter to anti-matter differences that we observe today. Finally, I will touch upon the Higgs boson’s connection to dark matter and how it can be used as a tool to reveal the dark universe.

Speaker: Monica Dunford (University of Heidelberg)

2:45 PM → 3:30 PM Keynote Physics Talks 6: Dark Matter - Dr. Belina von Krosigk, Hertha-Sponer Prizewinner 2023, KIT

Keynote

2:45 PM Towards the lightest dark matter in direct searches

In the last decades, astronomical observations have consistently indicated that most of the matter in the Universe remains hidden to even the most sensitive telescopes because it is nonluminous - because it is dark. Observing the respective dark matter particles became one of the most tantalizing endeavors of modern physics. A new generation of large exposure direct search experiments is at the ready to observe weak-scale dark matter particles, with their successors already in the planning. At the same time a new era has begun towards a direct detection of ever lighter dark matter candidates. Novel detector designs are reaching ultra-low detection thresholds with which new detection channels can be exploited. State-of-the-art direct detection searches most sensitive to light dark matter will be reviewed together with an outlook on where the near future is expected to take us in this quest towards dark matter discovery in the laboratory.

Speaker: Belina von Krosigk (Karlsruhe Institute of Technology)

20221127_DPT_BvKrosigk.pdf

3:30 PM → 4:00 PM Farewell

4:00 PM → 5:00 PM Coffee