## Semesterübersicht Wintersemester 2022/2023

24 Oct 2022

### Seminar about Experimental Particle and Astroparticle Physics (ETAP)

###### Institut für Physik12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum
Olivera Vujinovic, Institut für Physik
at Zoom

### RIND seminar on Mathematical Physics and String Theory

###### U. Mainz, LMU Munich, U. Heidelberg, U. Vienna16 Uhr c.t., Munich
 Albrecht Klemm, Bonn U. Recently it has been realized that the parameter dependence of Feynman integrals in dimensional regularisation can be calculated explicitly using period-- and chain integrals of suitably chosen Calabi-Yau motives, where the transcendentality weight of the motive is proportional to the dimension of the Calabi Yau geometry and the loop order of the Feynman graphs. We exemplify this for the Banana graphs, the Ice Cone graphs and the Train Track graphs in two dimensions. In the latter case there is a calculational very useful relation between the differential realisation of the Yangian symmetries and the Picard-Fuchs system of compact Calabi-Yau spaces M as well as between the physical correlations functions and the quantum volume of the manifolds W that are the mirrors to M. at Zoom
25 Oct 2022

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Dr hab. Wojciech Gawlik, JU Krakow, PL I will begin with a historical introduction starting from Michael Faraday’s discovery of the magneto-optical phenomena and the basic physics behind it. Next, I will present the revolution caused by the advent of lasers in magneto-optics studies and the developments which made the nonlinear magneto-optics one of the most precise measurement techniques. While focusing on hot atomic-vapor samples, I will also present some magneto-optic studies with cold, trapped atoms and colour centers in diamonds and their applications to magnetometry.
26 Oct 2022

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
 Dr. Chien-Yeah Seng, Univ. Bonn The precision measurement of the top-row Cabibbo-Kobayashi-Maskawa (CKM) matrix element $V_{ud}$ from beta decays of pion, neutron and nuclei plays an important role in low-energy precision tests of Standard Model (SM) predictions. The recent observation of an apparent deficit of the top-row CKM unitarity has attracted wide attentions and provided hints for physics beyond the Standard Model (BSM). Higher precision for the $V_{ud}$ extraction is needed to confirm (or reject) such an observation; in this talk the referent will discuss some ongoing efforts from the theory and experimental side to achieve this goal.Slides here...

### SPICE-Spin+X Seminar

###### TUK and JGU15:00 Uhr s.t.
James McIver, MPSD and Columbia University
##### Ultrafast optoelectronic probes of quantum materials
at Zoom and SPICE YouTube Channel

27 Oct 2022

### Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

###### Institut für Physik14:00 Uhr s.t., IPH Lorentzraum 05-127
 Prof. Dr. hab. Wojciech Gawlik, Jagiellonian University, Poland By simultaneous application of a laser and two microwave fields upon a spin system (e.g. NV centers in diamond) one can observe magnetic resonance structures with two-component, composite shapes of nested Lorentzians with different widths. One component is regularly power-broadened, whereas the linewidth of the other one undergoes field-induced stabilization and becomes power-independent. The observed stabilization appears to be a general phenomenon that occurs in open systems. It is caused by the competition between coherent driving and non-conservation of populations and can be interpreted in terms of specific bright and dark combinations of state populations. Bio: Studied physics at the Jagiellonian University in Kraków (MSc in 1970), 1972-74 worked in the Physikalisches Inst. der Uni Heidelberg (with G. zu Putlitz), PhD in 1975 (Uni Kraków). Longer research stays: Reading (GB) with G.W. Series, Munich with H. Walther, Paris with S. Haroche, Boulder with A. Gallagher, Berkeley with D. Budker. Head of the Atomic Optics Dept. (1990-94) and Photonic Dept. (2003-2017) in Jagiellonian Univ. (Kraków), since 2018 Professor Emeritus at the Institute of Physics Jagiellonian University.
31 Oct 2022

### Seminar about Experimental Particle and Astroparticle Physics (ETAP)

###### Institut für Physik12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum
Liam O'Sullivan, Institut für Physik
at Zoom

### RIND seminar on Mathematical Physics and String Theory

###### U. Mainz, LMU Munich, U. Heidelberg, U. Vienna16 Uhr c.t.
 Lorenz Eberhardt, IAS I will revisit string one-loop amplitudes in this talk. After reviewing the basics, I will explain how Witten’s iepsilon prescription gives a manifestly convergent representation of the amplitude. I will then consider the imaginary part of the amplitude and show directly that it satisfies the standard field theory cutting rules. This leads to an exact representation of the imaginary part of the amplitude. I will also discuss physical properties of the imaginary part such as the singularity structure of the amplitude, its Regge and high energy fixed-angle behaviour and low-spin dominance. Finally, I will tease how Rademacher’s contour can be used to evaluate the full one-loop open string amplitude exactly in terms of a convergent infinite sum. at Zoom
02 Nov 2022

### SPICE-Spin+X Seminar

###### TUK and JGU15:00 Uhr s.t.
Eric Fullerton, UC San Diego
##### Stripe domain phases in chiral magnetic systems with perpendicular anisotropy
at Zoom and SPICE YouTube Channel

03 Nov 2022

### Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

###### Institut für Physik14:00 Uhr s.t., IPH Lorentzraum 05-127
 Dr. Benjamin Stickler, Imperial College London, Dept. of Physics Controlling the quantum dynamics of massive and complex objects, such as large molecules and nanoparticles, requires a detailed understanding of the interaction between their many interacting degrees of freedom and control fields. In this talk, I will discuss how light scattering induces non-reciprocal interactions between co-levitated objects [1], how the rotational quantum interference of nanoparticles with embedded nitrogen-vacancy centres gives rise to novel quantum phenomena [2,3], and how diffraction of chiral molecules can prepare superpositions of molecular configurations [4]. These examples illustrate the potential of macro-mechanical quantum systems for novel force and torque sensing schemes and for high-mass tests of quantum physics. [1] Rieser, Ciampini, Rudolph, Kiesel, Hornberger, Stickler, Aspelmeyer, and Delić, Tunable light-induced dipole-dipole interaction between optically levitated nanoparticles, Science 377, 987 (2022). [2] Stickler, Hornberger, and Kim, Quantum rotations of nanoparticles, Nat. Rev. Phys. 3, 589 (2021). [3] Rusconi, Perdriat, Hétet, Romero-Isart, and Stickler, Phys. Rev. Lett. 129, 093605 (2022). [4] Stickler, Diekmann, Berger, Wang, Phys. Rev. X 11, 031056 (2021). Short Bio: I studied Chemistry and Physics at TU Graz, and received my PhD in Physics form the University of Graz in 2013. I held postdoc positions at the University of Duisburg-Essen and at Imperial College London (as a Marie Sklodowska Curie Fellow). I obtained my Habilitation at the University of Duisburg Essen in 2022, where I now work on the theory of macroscopic quantum physics and levitated nanomechanics.. In 2022, I was elected into the NRW Academy of Sciences and Arts as a Young Fellow and I was recently admitted to the prestigious Heisenberg Programme by the DFG.
07 Nov 2022

### Seminar about Experimental Particle and Astroparticle Physics (ETAP)

###### Institut für Physik12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum
Ioana Caracas, Institut für Physik
at Zoom

08 Nov 2022

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Dr. Horst Schmidt-Böcking, University of Frankfurt In der Nacht vom 7. auf den 8. Februar 1922 gelang es Walther Gerlach und Otto Stern im sogenannten Stern-Gerlach-Experiment SGE, zum ersten Male das magnetische Moment eines Atoms, des Silberatoms, zu messen und den Beweis zu erbringen, dass Arnold Sommerfelds und Pieter Debyes Postulat der Richtungsquantelung von atomaren magnetischen Momenten in einem äußeren Magnetfeld der Wahrheit entsprach. Das Messprinzip des Experimentes als hochauflösendes Impulsspektrometer für einzelne Atome im Vakuum und der historische Weg der Durchführung dieses Experimentes werden dargestellt. Das Ergebnis des SGE zeigte damit auch erstmals, dass auch die inneratomaren Drehimpulse gequantelt sind. Die Bedeutung des SGE für die Entwicklung der Quantenphysik besprochen.

### Theorie-Palaver

###### Institut für Physik14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor)
 Cem Eröncel, DESY Axion-like-particle (ALP) is a well-motivated candidate for dark matter, and it has been subject to extensive theoretical and experimental research in recent years. The most popular ALP production mechanism studied in the literature is the misalignment mechanism, where the ALP field initially has negligible kinetic energy and starts oscillating when its mass becomes comparable to the Hubble scale. Recently, a new mechanism called Kinetic Misalignment has been proposed where the ALP field receives large kinetic energy at early times due to the explicit breaking of the Peccei-Quinn symmetry. This causes a delay in the onset of oscillations so that the ALP dark matter parameter space can be expanded to lower values of the axion decay constant. At the same time, the ALP fluctuations grow exponentially via parametric resonance in this setup, and most of the energy in the homogeneous mode is converted to ALP particles. This process is known as fragmentation. In this talk, I will discuss the observational consequences of fragmentation for the axion mini-clusters and show that a sizable region of the ALP parameter space can be tested by future experiments that probe the small-scale structure. at Zoom
09 Nov 2022

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
 Prof. Dr. Alessandro Roggero, Univ.Trento, Italy In extreme astrophysical environments like supernova explosions, the large neutrino density can lead to collective flavor oscillations driven by neutrino-neutrino interactions. These phenomena are important to describe flavor transport and have potentially important consequences for both the explosion mechanism and nucleosynthesis in the ejected material. Even simple models of neutrino-neutrino interactions require the solution of a challenging many-body problem whose exact solution requires exponential resources in general. In this talk the referent will describe the physics of collective flavor oscillations and present the recent efforts to simulate the real-time flavor dynamics of two-flavor neutrinos using current generation quantum computers based on both superconducting qubits as well as trapped ions.
10 Nov 2022

### Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

###### Institut für Physik14:00 Uhr s.t., IPH Lorentzraum 05-127
 Dr. Anna Ermakova, MPI Mainz Color centers in diamonds offer wonderful sensing possibilities in the case of the detection of magnetic or electric fields or temperature. Color centers in nanodiamonds can be incorporated into the biological systems to investigate them. One of the biggest advantages of quantum sensors based on nanodiamonds is that they operate at room temperature or higher. Therefore, they can be used to study living systems. We investigate how nanodiamonds can be brought into the living system in the most efficient way and what information we can get from them. Bio: Studied physics in Belarusian State University (MSc in 2011), PhD in physics (magna cum laude) with Fedor Jelezko at Ulm University, Institute for Quantum Optics (2011-2016). From 2017 to 2021 she held positions as a postdoc at Ulm University, researcher at Silicon Austria Lab GmbH, and a senior scientist at MPIP (Mainz). Since 2022 – Anna is Independent Group Leader at Max-Planck-Institute for Polymer Research, Mainz, Germany supported by Carl-Zeiss Foundation, her group works on investigating potential of Nanodiamonds for intracellular magnetometry and thermometry, novel all-optical sensing methods, and cell metabolism processes.

### GRK 2516 Soft Matter Seminar

###### Uni Mainz14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7
 Gokul Govind, JGU, Physics Sequence controlled polymerization is an inevitable process in natural systems. The amino acid sequence arrangement is the vital part in determining the structure function of proteins. This process of selection and formation of sequence interests scientists to build polymers that are made of self-assembled monomers that interact through Van der Waals interactions such as hydrogen bonds and hydrophobic interactions. In this talk I will be discussing the copolymerization of two monomers that are having hydrophobic and hydrophilic domains whose interplay induces a supramolecular polymerization in water. We discuss the concentration factors that can contribute to the formation of homopolymers and copolymers with different sequences. References : Macromol. Rapid Commun. 2021, 2100473 Macromolecules 2019, 52, 7661−7667 J. Am. Chem. Soc. 2020, 142, 16, 7606–7617 at Zoom

### GRK 2516 Soft Matter Seminar

###### Uni Mainz15:00 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7
 Bhuwan Poudel, MPI-Polymer Research It is crucial to understand how stimuli-responsive polymer surfaces, such as polymer brushes, accommodate nanoparticles and how the presence of nanoparticles alters the structural and dynamical properties of the brushes in order to use the brush/NPs hybrid in optimal applications. We plan on answering this question by carrying out detailed molecular dynamics simulations. As a first step toward the project's goal, we investigated the properties of brushes and studied how a nanoparticle interacts with them. at Zoom
11 Nov 2022

### Theorie-Palaver

###### Institut für Physik15:00 Uhr s.t., HIM building, room 02.111
Pere Masjuan, Universitat Autonoma de Barcelona
##### The role of Pade approximants as fitting functions

Note the special time and room.

14 Nov 2022

### Seminar about Experimental Particle and Astroparticle Physics (ETAP)

###### Institut für Physik12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum
Martin Rongen, Institut für Physik
at Zoom

### RIND seminar on Mathematical Physics and String Theory

###### U. Mainz, LMU Munich, U. Heidelberg, U. Vienna16 Uhr c.t.
 Raghu Mahajan, Stanford U. We use insights from string field theory to analyze and cure the divergences in the cylinder diagram in minimal string theory, with both boundaries lying on a ZZ brane. Minimal string theory refers to the theory of two-dimensional gravity coupled to a minimal model CFT that serves as the matter sector; it includes JT gravity as a limiting case. ZZ branes are akin to D-instantons, and give rise to features that reflect the underlying discreteness of the dual theory. The exponential of the cylinder diagram represents the one-loop determinant around the instanton saddle. The finite result for this one-loop constant computed using the string field theory procedure agrees precisely with independent calculations in the dual double-scaled matrix integrals performed by several authors many years ago. at Zoom
15 Nov 2022

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Dr. Peter Spichtinger, JGU Institute for Atmospheric Physics Ice clouds constitute an important component in the Earth-atmosphere system. Like all clouds, they influence the hydrological cycle and the energy budget of the system. Thereby, the partial reflection of incident radiation results into a cooling effect (albedo effect), and the absorption and re-emission of thermal radiation results into a warming effect (greenhouse effect). However, for ice clouds in the tropopause region the net effect (warming or cooling) is unclear, because both opposite effects are of the same order of magnitude. Thus, the net effect depends on further properties of the multiscale system of ice clouds, such as the size and shape of the crystals, as well as the formation of structures within clouds resulting into heterogeneous media. In particular, the formation of structures in (ice) clouds is relatively poorly known so far and requires further investigation. In this talk we investigate processes and phenomena on different scales of ice clouds. We start with single crystals and their properties, as well as methods to measure these particles. To represent the ensemble ice cloud, models have to be developed and further investigated. The formulation of reduced order models leads us to ice clouds as nonlinear oscillators. The interaction on different scales and of different processes finally leads to the formation of characteristic structures. These investigations are current research and are carried out in interdisciplinary collaboration.

### Theorie-Palaver

###### Institut für Physik14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor)
 Mathias Becker, JGU Mainz A non-minimal dark sector could explain why WIMP dark matter has evaded detection so far. Based on the extensively studied example of a simplified t-channel dark matter model involving a colored mediator, we demonstrate that the Sommerfeld effect and bound state formation must be considered for an accurate prediction of the relic density and thus also when inferring the experimental constraints on the model. We find that parameter space thought to be excluded by LHC searches and direct detection experiments still remains viable. Moreover, we point out that the search for bound state resonances at the LHC offers a unique opportunity to constrain a wide range of dark matter couplings inaccessible to prompt and long-lived particle searches.
16 Nov 2022

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
 Dr. Graziano Venanzoni, Frascati, Italy The latest measurement of the muon g-2 announced at Fermilab exhibits a 4.2$\sigma$ discrepancy from the currently accepted Standard Model prediction. The main source of uncertainty on the theoretical value is represented by the leading order hadronic contribution $a_{\mu}^{HLO}$, which is traditionally determined through a data-driven dispersive approach. A recent calculation of $a_{\mu}^{HLO}$ based on lattice QCD is in tension with the dispersive evaluation, and reduces the discrepancy between theory and experiment to 1.5$\sigma$. An independent evaluation of $a_{\mu}^{HLO}$ is therefore required to solve this tension and consolidate the theoretical prediction. The MUonE experiment proposes a novel approach to determine $a_{\mu}^{HLO}$ by measuring the running of the electromagnetic coupling constant in the space-like region, via $\mu-e$ elastic scattering. The measurement will be performed by scattering a 160 GeV muon beam, currently available at CERN's North Area, on the atomic electrons of a low-Z target. A Test Run on a reduced detector is planned to validate this proposal. The status of the experiment in view of the Test Run and the future plans will be presented.Slides here...

### SPICE-Spin+X Seminar

###### TUK and JGU15:00 Uhr s.t.
Yoav William Windsor, FH Institute of the MPS and TU Berlin
##### Towards a "complete" picture of ultrafast dynamics in the 2D ferromagnet FGT
at Zoom and SPICE YouTube Channel

21 Nov 2022

### Seminar about Experimental Particle and Astroparticle Physics (ETAP)

###### Institut für Physik12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum
Patrycja Potepa, Institut für Physik
at Zoom

22 Nov 2022

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Dr. Erwin Frey, University of Munich Protein pattern formation is essential for the spatial organization of intracellular processes like cell division, and flagellum positioning. A prominent example of intracellular patterns is the oscillatory pole-to-pole oscillations of Min proteins in E. coli whose function is to ensure precise cell division. Cell polarization, a prerequisite for processes such as stem cell differentiation and cell polarity in yeast, is also mediated by a diffusion-reaction process. More generally, these functional modules of cells serve as model systems for self-organization, one of the core principles of life. Under which conditions spatio-temporal patterns emerge, and how these patterns are regulated by biochemical and geometrical factors are major aspects of current research. In this talk I will review recent theoretical and experimental advances in the field of intracellular pattern formation, focusing on general design principles and fundamental physical mechanisms.

### Theorie-Palaver

###### Institut für Physik14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor)
 Alfredo Guerrera, Padua U. and INFN Axion--Like--Particles are among the most economical and well motivated extensions of the Standard Model. In this talk ALP production from hadronic and leptonic meson decays are studied. The hadronization part of these decay amplitudes has been obtained using Brodsky--Lepage method or LQCD, at needs. In particular, the general expressions for ALP emission in mesonic s-- and t--channel tree--level processes are thoroughly discussed, for pseudoscalar and vector mesons. Accordingly, exact results as well as some useful approximation for meson-to-meson and meson leptonic decay amplitudes are presented. I will the discuss the phenomenology of various decays and highlight the most robust in terms of experimental searches and theoretical predictions. Finally, bounds on the (low--energy effective Lagrangian) ALP--fermion couplings are derived, from present and future flavour experiments. If I have time left I'll also cover some of the new form factors calculations in B mesogenesis. at Zoom
23 Nov 2022

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
 Francesca Carlin, Berlin (Please note: Event will take 2 hours) Evaluations and selections determine scientific careers possibly like no other factor. Knowing that they are also susceptible to bias and preconceptions, how can we ensure a fair recruitment process and assure to pick the best candidate? Together, we want to reflect how we hold discussions in selection committees (on all career levels!) and learn what practices prove helpful in guaranteeing more equitable opportunities for all applicants. Please register through prisma@uni-mainz.de to receive preparatory material.Slides here...
24 Nov 2022

### Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

###### Institut für Physik14:00 Uhr s.t., IPH Lorentzraum 05-127
 Dr. Lars von der Wense, LMU München Optical atomic clocks are today’s most accurate time-keeping devices. They achieve stunning relative accuracies in the range of 10-18, corresponding to an error of 1 second in 30 billion years. An even improved accuracy is expected to be achieved by a nuclear optical clock, since the nucleus is significantly less sensitive to external influences than the atomic shell. Developing a nuclear optical clock requires laser spectroscopy of a nuclear transition, an objective which has so far not been achieved, but which has come into reach due to recent gain of knowledge. In this talk I will give an overview over the recent progress that has been made toward the development of a nuclear optical clock. I will introduce several experiments that are currently in preparation aiming toward first-time laser spectroscopy of a nuclear transition. Finally, I will introduce the investigations planned within the framework of the newly funded BMBF project “NuQuant”.

### GRK 2516 Soft Matter Seminar

###### Uni Mainz14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7
 Seraphine Wegner, WWU Münster Bottom-up synthetic biology aims to construct cell-like systems starting from molecular building blocks. These synthetic cells give insight into the molecular details and principles that give rise to cell function. Many functions in cells arise directly from the spatial and temporal regulation of cell-matrix and cell-cell interactions. In this talk, I will present strategies of how such spatiotemporal control over adhesions of synthetic and natural cells can be achieved with visible light and functions that arise from these. The photoswitchable adhesions allow us recapitulate cell migration, to self-assemble and self-sort cells into multicellular functional architectures with high precision, regulate their interactions with synthetic materials, program cell to cell communication and to study the underlying biology. Synthetic minimal cells, which reduce complexity and yet capture key features of natural cells, allow us to quantify and correlate cell behavior with molecular information. Further, complementary approaches pursued with synthetic minimal cells as well as bacterial and mammalian cells allow translating concepts between different systems and integration into hybrid structures. Overall, our work on one hand provides insight into underlying design principles of life and on the other hand engineer new synthetic cell biology. at Zoom
28 Nov 2022

### RIND seminar on Mathematical Physics and String Theory

###### U. Mainz, LMU Munich, U. Heidelberg, U. Vienna16 Uhr c.t.
 Enno Keßler, MPI-M Bonn J-holomorphic curves or pseudoholomorphic curves are maps from Riemann surfaces to symplectic manifolds satisfying the Cauchy-Riemann equations. J-holomorphic curves are of great interest because they allow to construct invariants of symplectic manifolds and those invariants are deeply related to topological superstring theory. A crucial step towards Gromov–Witten invariants is the compactification of the moduli space of J-holomorphic curves via stable maps which was first proposed by Kontsevich and Manin. In this talk, I want to report on a supergeometric generalization of J- holomorphic curves and stable maps where the domain is a super Riemann surface. Super Riemann surfaces have first appeared as generalizations of Riemann surfaces with anti-commutative variables in superstring theory. Super J-holomorphic curves couple the equations of classical J-holomorphic curves with a Dirac equation for spinors and are critical points of the superconformal action. The compactification of the moduli space of super J- holomorphic curves via super stable maps might, in the future, lead to a supergeometric generalization of Gromov-Witten invariants. Based on arXiv:2010.15634 [math.DG] and arXiv:1911.05607 [math.DG], joint with Artan Sheshmani and Shing-Tung Yau. at Zoom

## aktuell

29 Nov 2022

### Theorie-Palaver

###### Institut für Physik14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor)
 Markus Fröb, U. Leipzig Perturbative Quantum Gravity (pQG), the effective quantum field theory of gravitational fluctuations around a given background, is currently the only experimentally accessible theory of quantum gravity. Its tree-level predictions, in the form of temperature fluctuations of the Cosmic Microwave Background, have been experimentally confirmed, and it is possible that loop corrections are accessible to future experiments. However, while the tree-level results are well understood also from a theoretical point of view, the diffeomorphism symmetry of gravity makes the construction of invariant observables very difficult beyond this. Only recently, this issue has been overcome, and a class of causal invariant observables has been constructed. I will discuss this construction and how it can be related to observations, and present some predictions of pQG for graviton loop corrections to the Newtonian gravitational potential and the Hubble rate, the local expansion rate of the universe. Lastly, I show that pQG also predicts that spacetime becomes non-commutative at the Planck scale, but in a different way from previous approaches. The talk is based (in particular) on the recent papers arXiv:1806.11124, 2108.11960, 2109.09753 and 2207.03345. at Zoom

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Dr. Katrin Amann-Winkel, MPI für Polymerforschung Mainz Water is ubiquitous and the most important liquid for life on earth. Although the water molecule is seemingly simple, various macroscopic properties of water are most anomalous, such as the density maximum at 4°C or the divergence of the heat capacity upon cooling. Computer-simulations suggest that the anomalous behaviour of ambient and supercooled water could be explained by a two state model of water. An important role in this ongoing debate plays the amorphous forms of water. Since the discovery of two distinct amorphous states of ice with different density (high- and low density amorphous ice, HDA and LDA) it has been discussed whether and how this phenomenon of polyamorphism at high pressures is connected to the occurrence of two distinct liquid phases (HDL and LDL). X-ray free electron laser allow us to investigate metastable states of supercooled water within nano- to microseconds. In my talk I will give an overview on our recent X-ray experiments on supercooled water and amorphous ices.
zukünftige Termine
30 Nov 2022

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
 Prof. Dr. Tetyana Galatyuk, GSI Darmstadt What happens when gold nuclei, accelerated to about 90% of the speed of light, strike gold nuclei at rest? For an extremely short time, t~10^-23 seconds, states of matter at extreme temperatures (10^12 K) and densities (>280 Mt/cm^3) are produced. The microscopic properties of the strong-interaction matter under extreme conditions of temperature and density is a topic of great current interest. Despite 18 orders of magnitude difference in system size and time, the conditions present in heavy-ion collisions share great overlap with the conditions of the strong-interaction matter in neutron-star mergers. The possibility to form and explore in the laboratory strong-interaction matter under extreme conditions is truly fascinating. The Compressed Baryonic Matter (CBM) experiment at FAIR has the potential to discover the most prominent landmarks of the QCD phase diagram expected to exist at high net baryon densities. The measurement of comprehensive set of diagnostic probes offers the possibility to find signatures of exotic phases, and to discover the conjectured first order deconfinement phase transition and its critical endpoint. In this talk the referent will focus on relevant observables to study criticality, emissivity, vorticity and equation-of-state of baryon rich matter. Particular emphasis is put on rare probes which are not accessible by other experiments in this energy range.

### SPICE-Spin+X Seminar

###### TUK and JGU15:00 Uhr s.t., Zoom
Alice Mizrahi, CNRS-Thales
##### Multilayer spintronic neural networks with radio-frequency connections
at Zoom and SPICE YouTube Channel

### Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)

###### JGU10:00 Uhr s.t., TUK, Building 76, Room 276 (LASE)
Prof. Victor L’vov, Dept. of Chemical and Biological Physics, Weizmann Institute of Science
at Zoom

01 Dec 2022

### Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)

###### JGU16:15 Uhr s.t., 01-122 Newton Raum
 Martin Beye, DESY Resonant inleastic X-ray scattering (RIXS) especially in the soft X-ray region has seen a tremendous increase in applicability and scientific insight over the recent years. This was largely enabled by progress in instrumentation and theoretical description. Now the time is ripe to apply RIXS to pressing problems and develop the technique further making full use of the capabilities of novel X-ray sources. In my talk, I will address three main themes from my research: 1. Time-resolved RIXS at free-electron lasers applied to relevant dynamic processes in chemistry (on surfaces, in liquids and in solid catalysts) 2. RIXS with micrometer spatial resolution to resolve domain dynamics in complex materials and on devices in-operando 3. Non-linear spectroscopies in the soft X-ray range to enhance information content and signal levels I will show and discuss experimental results from all research themes and point to future development directions.

### Seminar über Theorie der kondensierten Materie / TRR146 Seminar

###### K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau15:00 Uhr s.t., Remote
Oliver Beckstein, Arizona State University

05 Dec 2022

### Seminar about Experimental Particle and Astroparticle Physics (ETAP)

###### Institut für Physik12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum
Rainer Wanke, Institut für Physik
at Zoom

06 Dec 2022

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Dr. Peter Hommelhoff, University of Erlangen Optical fields can now be controlled with similar degrees of freedom as microwave fields for many decades already: we can now control not just the pulse envelope but also the optical carrier field. With few cycle laser pulses, this allows steering of electrons in unprecedented ways. I will give an overview over recent experiments we performed mainly with the atomically thin material graphene. Here we can drive the intraband motion of electrons but also interband transitions. For the intense ultrashort fields we employ, these processes become intricately coupled - a hallmark of strongfield physics. In particular, we could observe subsequent coherent Landau-Zener transitions, leading to Landau-Zener-Stückelberg-Majorana interferometry, representing fully coherent electron dynamics in a room-temperature material. In the second part of the talk, we will shine light on the graphene-gold interface and how it will add to the currents we can excite. Because of the different symmetries involved, we can disentangle virtual and real carrier excitations. With these insights, we have recently demonstrated a first Boolean logic gate based on two laser pulses carrying the logic information in the carrier envelope phase, which might bring lightwave or petahertz electronics closer to reality.

### Theorie-Palaver

###### Institut für Physik14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor)
 Johanna Erdmenger, Würzburg U. TBA at Zoom
07 Dec 2022

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
 Prof. Dr. Tim Cohen, CERN, Switzerland The referent will describe some recent work on applying Effective Field Theory (EFT) methodology to three different physically interesting systems. First he will explain the philosophy and general methodology of EFT. He will then present three short vignettes. The first has to do with techniques for systematically computing the EFT parameters from a given more fundamental description. The second will show how EFT can be used to understand the behavior of quantum fields in an inflationary background, with applications to light scalar fields and the inflaton itself. And in the third, the referent will show how EFT ideas can be applied to systematically improve a numerical technique for quantum field theory known as Hamiltonian truncation.
08 Dec 2022

### Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

###### Institut für Physik14:00 Uhr s.t., IPH Lorentzraum 05-127
 Dr. Nikita Kavokine, MPI for Polymer Research, Mainz Liquids are usually described within classical physics, whereas solids require the tools of quantum mechanics. I will show how in nanoscale systems this distinction no longer holds. At these scales, liquid flows may in fact exhibit quantum effects as they interact with electrons in the solid walls. I will first discuss the quantum friction phenomenon, where charge fluctuations in the liquid interact with electronic excitations in the solid to produce a hydrodynamic friction force. Using many-body quantum theory, we predict that this effect is particularly important for water flowing on carbon-based materials, and we obtain experimental evidence of the underlying mechanism from pump-probe terahertz spectroscopy. I will then show how the theory can be pushed one step further to describe hydrodynamic Coulomb drag – the generation of electric current by a liquid in the solid along which it flows. This phenomenon involves a subtle interplay of electrostatic and electron-phonon interactions, and suggests strategies for designing materials with low hydrodynamic friction. Bio: Nikita Kavokine obtained a Bachelor in Chemistry and a Master in Theoretical Physics from Ecole Normale Supérieure (ENS) in Paris. He continued at ENS for his PhD, in the group of Prof. Lydéric Bocquet, working on both theory and experiments in nanoscale fluid dynamics. He then obtained a Flatiron Research Fellowship and spent a year in New York, learning advanced numerical methods for condensed matter systems. He is now a postdoctoral fellow at the Max Planck Institute for Polymer Research. His research is at the interface between ‘hard’ and ’soft’ condensed matter, focussing on the quantum behavior of liquids near solid surfaces.

at Zoom

### GRK 2516 Soft Matter Seminar

###### Uni Mainz15:00 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7
Janka Bauer, JGU, Physics
at Zoom

13 Dec 2022

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Michael E. Flatté, University of Iowa Electric manipulation of magnetization is essential for the integration of magnetic functionalities in integrated circuits. Spin-orbit torque (SOT), originating from the coupling of electron spin and orbital motion through spin-orbital interaction, can effectively manipulate magnetization. Symmetry breaking plays an important role in spintronics based on SOT. SOT requires inversion asymmetry in order to have a net effect on magnetic materials, which is commonly realized by spatial asymmetry: a thin magnetic layer sandwiched between two dissimilar layers. This kind of structure restricts the SOT by mirror and rotational symmetries to have a particular form: an “antidamping-like” component oriented in the film plane even upon reversal of the magnetization direction. Consequently, magnetization perpendicular to the film plane cannot be deterministically switched with pure electric current. To achieve all-electric switching of perpendicular magnetization, it is necessary to break the mirror and rotational symmetries of the sandwiched structure.
14 Dec 2022

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
 Dr. Gaia Lanfranchi, Frascati, Italy With the establishment and maturation of the experimental programs searching for New Physics with sizeable couplings at the LHC, there is an increasing interest in the broader particle and astroparticle community for exploring the physics of light and feebly-interacting particles (FIPs) as a paradigm complementary to a New Physics sector at the TeV scale and beyond. SHADOWS is a new experiment proposed at the CERN North Area to search for a large variety of FIPs produced in the interactions of a proton beam with a dump. It will use the 400 GeV primary proton beam extracted from the CERN SPS currently serving the NA62 experiment. SHADOWS can expand the exploration for a large variety of FIPs well beyond the state of the art in the MeV-GeV mass range which is allowed by cosmological and astrophysical observations and become one of the main players in the search for FIPs at accelerators in the next decade. After an introduction about the current plans for searching for FIPs at CERN within the Physics Beyond Colliders activity the referent will present the status of the SHADOWS project.
20 Dec 2022

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Dr. Sarah Köster, Uni Göttingen We have about 200 different types of cell in our body, and each of them has very special mechanical properties. Illustrative examples are contracting muscle cells, migrating immune cells or elastic red blood cells. There intriguing mechanical properties are to a great part determined by the so-called cytoskeleton (the “skeleton of the cell”), a composite biopolymer network composed of three filament systems – intermediate filaments, actin filaments and microtubules – along with cross-linkers and molecular motors. In my talk, I will focus on intermediate filaments, the most flexible and the most extensible ones among the different types of filament, with an intriguing non-linear behavior. It has been shown previously that the presence of intermediate filaments in a cell has an influence on its mechanics. Here we unravel different contributions to network properties and cell mechanics, such as the assembly kinetics and mechanical properties of the individual filaments, filament-filament interactions, and network rheology. To explain our experimental results on molecular grounds, we design models that include the strictly hierarchical build-up of the filaments and non-equilibrium transitions between folded and un-folded states. Taken together, the experiments and the modelling indicate that intermediate filaments serve as “safety belts” and shock absorbers” for the cell, thus avoiding damage at strong and fast impact, while maintaining flexibility (e.g., during cell motility).
09 Jan 2023

### Seminar about Experimental Particle and Astroparticle Physics (ETAP)

###### Institut für Physik12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum
Johannes Balz, Institut für Physik
at Zoom

10 Jan 2023

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
Dr. Nico Döttling, Helmholzt Center for Information Security (CISPA) in Saarbrücken

11 Jan 2023

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
 Dr. Valentina Santoro, ESS, Lund, Sweden The European Spallation Source, ESS, currently under construction in Lund, will be the world’s most powerful facility for research using neutrons. Supported by 3MEuro Research and Innovation Action within the EU Horizon 2020 program, a design study (HighNESS) is now underway to develop a second neutron source below the spallation target. Compared to the first source, located above the spallation target and designed for high cold and thermal brightness, the new source will provide a higher intensity (the total number of neutrons from the moderator), and a shift to longer wavelengths in the spectral regions of Cold (4-10 ˚A), Very Cold (10-100 ˚A), and Ultra Cold (> 500 ˚A) neutrons. The core of the second source will consist of a large liquid deuterium moderator to deliver a high flux of cold neutrons and to serve secondary VCN and UCN sources, for which different options are under study. The features of this new source will boost several areas of condensed matter research and will also provide unique opportunities in fundamental physics with the neutron antineutron oscillations experiment NNBAR. This experiment will search for the baryon number violating process of n → ¯n oscillation with a sensitivity of three orders of magnitude over the previously attained limit obtained at the Institut Laue-Langevin ILL. As a part of the HighNESS project work is ongoing to deliver the Conceptual Design Report of the experiment. Concerning the design of the Ultra Cold Neutron and Very cold neutron source for the ESS, a digital workshop has been held from February 2nd to February 4th, 2022 where experts from various laboratories and Universities have gathered to propose and discuss ideas and challenges for the development of these sources. During the course of the workshop, several possibilities have been identified on where to locate the VCN and UCN sources. The UCN source could be placed in close vicinity or at some distance from the primary cold source. Regarding the VCN source, we have identified two possibilities. In the first option, the VCNs are extracted from the main CN source using advanced reflectors. While in the other case we make use of a dedicated VCN converter, for which a material capable of delivering a high flux of VCNs is needed. From the point of view of neutronic performance, two promising materials, which are under study in the HighNESS project, are solid deuterium at about 5 K and deuterated clathrate hydrates at around 2 K. In summary in the the talk, the referent will discuss the HighNESS project, the status of the NNBAR experiment and all the possibilities for a dedicated UCN and VCN source at the ESS.
16 Jan 2023

at Zoom

17 Jan 2023

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
Prof. Georg von Freymann, TU Kaiserslautern

18 Jan 2023

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
Dr. Anatael Cabrera, Paris, France

19 Jan 2023

### Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

###### Institut für Physik14:00 Uhr s.t., IPH Lorentzraum 05-127
 Prof. Giuseppe Vallone, University of Padova, Italy TBA
24 Jan 2023

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Dr. Markus Klute, KIT „I think we have it“ – with these words, the then Director General of CERN, Rolf-Dieter Heuer, commented on July 4th, 2012 the detection of a new elementary particle at the Large Hadron Collider (LHC). The search for the Higgs boson, which had lasted almost 50 years, had reached its goal. With the discovery of the Higgs boson, a new era began at the LHC, the precise measurement of the particle's properties. With the help of these properties, conclusions can be drawn about the fundamental structure of the universe and matter. In this colloquium, I will discuss the latest result and prospects in the quest to decipher the Higgs boson.
25 Jan 2023

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
Prof. Dr. Peter von Ballmoos, IRAP, Toulouse, France

26 Jan 2023

### Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

###### Institut für Physik14:00 Uhr s.t., IPH Lorentzraum 05-127
 Prof. Vahid Sandoghdar, Max-Planck-Institut für die Physik des Lichts, Erlangen TBA
31 Jan 2023

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
Dr. Philipp Schmidt-Wellenburg, PSI Switzerland

01 Feb 2023

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
Prof. Dr. Steen Hannestad, Univ. Aarhus, Denmark

02 Feb 2023

### Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

###### Institut für Physik14:00 Uhr s.t., IPH Lorentzraum 05-127
 Prof. Stephan Schiller, Heinrich-Heine-Universität Düsseldorf, Institut für Experimentalphysik TBA
07 Feb 2023

### Physikalisches Kolloquium

###### Institut für Kernphysik16:15 Uhr s.t., HS KPH
 Prof. Dr. Tom Aumann, TU Darmstadt & GSI Darmstadt Reactions with short-lived nuclei are key to understand the properties of neutron-rich nuclei and neutron-rich nuclear matter. In recent years, quasi-free scattering experiments have been developed and established for experiments with radioactive beams at GSI and RIKEN. The inverse kinematics of the reaction opens thereby the possibility for a complete characterisation of the final state, which results in an almost background-free measurement. Recent results with stable and radioactive beams will be discussed including the first measurement of short-range correlations in inverse kinematics, the observation of alpha clusters at the surface of heavy nuclei, as well as the observation of a correlated four-neutron state. The perspective for a precise determination of the neutron-neutron scattering length using the 6He(p,p alpha)2n reaction will be discussed as well.

### Theorie-Palaver

###### Institut für Physik14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor)
Weiguang Jiang, JGU Mainz
at Zoom

08 Feb 2023

### PRISMA+ Colloquium

###### Institut für Physik13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7
Prof. Dr. Julien Lesgourges, Aachen

09 Feb 2023

### Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

###### Institut für Physik14:00 Uhr s.t., IPH Lorentzraum 05-127
 Prof. Dr. Immanuel Bloch, Max-Planck-Institute of Quantum Physics, Garching TBA