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Jahresübersicht für das Jahr 2021

Übersicht 2020 - Übersicht 2021 - Übersicht 2022

07 Jan 2021

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

Institut für Physik

14 Uhr c.t., None

Prof. Dr. Antoine Browaeys, Laboratoire Charles Fabry, Palaiseau, France
This talk will present our effort to control and use the dipole-dipole interactions between cold atoms in order to implement spin Hamiltonians useful for quantum simulation of condensed matter or quantum optics situations. We trap individual atoms in arrays of optical tweezers separated by a few micrometers. We create almost arbitrary geometries of the atomic arrays in two and three dimensions up to about 200 atoms. To make the atoms interact, we either excite them to Rydberg states or induce optical dipoles with a near-resonance laser. Using this platform, we have in particular explored quantum magnetism, topological synthetic quantum matter, and a new light-matter interface.
at Zoom

11 Jan 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Bastian Schlag, Institut für Physik
Vertexing in ATLAS
at Zoom for now

12 Jan 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Zheng-Tian Lu, University of Science and Technology of China
The long-lived noble-gas isotope 81Kr is the ideal tracer for water and ice with ages of 105 - 106 years, a range beyond the reach of 14C. 81Kr-dating, a concept pursued over the past five decades, is finally available to the earth science community at large. This is made possible by the development of the Atom Trap Trace Analysis (ATTA) method, in which individual atoms of the desired isotope are captured and detected. ATTA possesses superior selectivity, and is thus far used to analyze the environmental radioactive isotopes 81Kr, 85Kr, and 39Ar. These three isotopes have extremely low isotopic abundances in the range of 10-17 to 10-11, and cover a wide range of ages and applications. In collaboration with earth scientists, we are dating groundwater and mapping its flow in major aquifers around the world. We are also dating old ice from the deep ice cores of Antarctica, Greenland, and the Tibetan Plateau. For an update on this worldwide effort, please google “ATTA Primer”.
at Recording of the presentation

13 Jan 2021

PRISMA Colloquium

Institut für Physik

13:00 Uhr s.t., None

Daniele Guffanti, Institute of Physics, JGU Mainz
The Sun, as all the other stars, is fueled for most of its life by the fusion of hydrogen into helium taking place in its core. Neutrinos produced in such reactions are the only direct probe to the innermost part of our star and real time messengers of its engine. Decades of experimental and phenomenological efforts allowed us to study in detail the driving energy production mechanism in the Sun, the proton-proton chain, which is responsible for ~99% of the Sun luminosity. The fusion processes accounting for the remaining 1% are believed to be catalyzed by the presence of Carbon, Nitrogen and Oxygen (CNO-cycle) in the Sun interior, but a direct evidence of the occurrence of such mechanism was still missing. After years-long efforts, the Borexino experiment at the Gran Sasso National Laboratories has recently reported the first direct observation of solar neutrinos produced in the CNO-cycle. In this talk I will present the Borexino findings and I will discuss the importance of CNO neutrinos for astrophysics and for our understanding of the Sun, particularly in connection to its chemical composition.
at Zoom

14 Jan 2021

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

Institut für Physik

14 Uhr c.t., None

Tanya S. Roussy, M.A., JILA (University of Colorado Boulder & NIST)
Over the past few decades, accelerators have been the traditional venue for new particle discoveries – but the paradigm is shifting. Accelerator energies are likely to remain on a plateau for some time, while atomic physics & precision measurement are in a remarkable period of progress. Some limits have advanced by a factor of 100 in less than 10 years, and laser technologies are being refined to exquisite levels. New Physics searches are already an established avenue in the atomic physics field; from atomic parity violation, to EDM searches, to equivalence principle tests. Happily, many of these platforms are well-suited to do double-duty as broadband dark matter searches. In this talk, I will explain the basics of our unique trapped-ion electron EDM search, how we used our recent data to constrain the gluon to axion-like particle coupling over seven mass decades, and how we solved some important methodological issues along the way.
at Zoom

Theoriekolloquium

Die Dozierenden der Theoretischen Physik

16:00 Uhr s.t., usually Newton-Raum, Staudinger Weg 9, 01-122

Dries Sels, New York University
Recent technological advances have put us at the brink of having access to small scale quantum computers capable of solving problems that cannot be tackled with classical computers. A limited number of algorithms have been proposed and their relevance to real world problems is a subject of active investigation. Solving problems relevant to chemistry are expected to be the first successful applications of quantum computers. In this talk, I will discuss a particular problem that can be solved efficiently on quantum computers: model inference for nuclear magnetic resonance (NMR) spectroscopy. I will give a broad introduction to quantum computing and NMR metabolomics assuming no prior knowledge of the subject.
at Zoom

15 Jan 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Nathalie Katsonis, University of Groningen, The Netherlands
TBA

18 Jan 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Eftychia Tzovara, Institut für Physik
ttH(bb) in ATLAS: inclusive and differential cross section
at Zoom for now

19 Jan 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Bernadett Weinzierl, University of Vienna, Austria
Aerosol particles are an important constituent of the global climate system. They not only affect the atmospheric radiation budget through scattering and absorption of solar radiation and through their role as cloud/ice nuclei but also impact air quality and human health. Both natural and human processes contribute to the global aerosol load. Whereas coarse‐mode aerosol (>1 μm diameter) mainly originates from natural aerosol sources, fine mode aerosol is frequently associated with human activities. Although substantial effort has been undertaken in the last decades to improve our knowledge about aerosols and their role in the global climate system, aerosol‐cloud‐radiation interactions still pose the largest uncertainty to estimates and interpretations of the Earth’s changing energy budget (IPCC, 2013). In order to decrease these uncertainties, research is necessary. Thereby, research aircraft like the German Aerospace Center (DLR) Falcon and the NASA DC‐8 provide unique platforms to study the horizontal and vertical distribution of aerosols and their microphysical, chemical and optical properties. In this talk, I will introduce aerosols in general, and discuss their effects on the atmosphere and climate. Furthermore, I will show selected results from airborne field experiments with the DLR research aircraft Falcon and the NASA research aircraft DC8 studying the long‐range transport of mineral dust (SALTRACE project), the global distribution of coarse mode aerosols (ATom project), and aerosol mixtures in the Eastern Mediterranean (A‐LIFE project).
at Zoom

Theorie-Palaver

Institut für Physik

14:30 Uhr s.t., None

Danny van Dyk, TUM, Munich
I will discuss theory predictions for exclusive b->s ll decays within the SM and beyond, with emphasis on the hadronic matrix elements. There are two categories of these matrix elements: local form factors, and nonlocal contributions arising from e.g. four-quark operators. I will report the status and report recent progress from QCD-based methods on the non-local hadronic matrix elements arising from intermediate charm states. A particular focus will be a recent derivation of a dispersive bound on the non-local matrix element as discussed in arXiv:2011.09813.
at Zoom

20 Jan 2021

PRISMA Colloquium

Institut für Physik

13:00 Uhr s.t., None

Jens Erler, JGU Mainz
The precise standard model
at Zoom

21 Jan 2021

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

Institut für Physik

14 Uhr c.t., None

Prof. Dr. Hatice Altug, EPFL Lausanne, CH
New health initiatives with global healthcare, precision medicine and point-of-care diagnostics are demanding breakthrough developments in biosensing and bioanalytical tools. Current biosensors are lacking precision, bulky, and costly, as well as they require long detection times, sophisticated infrastructure and trained personnel, which limit their application areas. My laboratory is focused on to address these challenges by exploiting novel optical phenomena at nanoscale and engineering toolkits such as nanophotonics, nanofabrication, microfluidics and data science. In particular, we use photonic nanostructures based on plasmonics and dielectric metasurfaces that can confine light below the fundamental diffraction limit and generate strong electromagnetic fields in nanometric volumes. In this talk I will present how we exploit nanophotonics and combine it with imaging, biology, chemistry and data science techniques to achieve high performance biosensors. I will introduce ultra-sensitive Mid-IR biosensors based on surface enhanced infrared spectroscopy for chemical specific detection of molecules, large-area chemical imaging and real-time monitoring of protein conformations in aqueous environment. Next, I will describe our effort to develop ultra-compact, portable, rapid and low-cost microarrays and their use for early disease diagnostics in real-world settings. Finally, I will highlight label-free optofluidic biosensors that can perform one-of-a-kind measurements on live cells down to the single cell level, and provide their prospects in biomedical and clinical applications.
at Zoom

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau

18:00 Uhr s.t., None

Scott Shell, UCSB, USA
tba
at Zoom

25 Jan 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Florian Thomas, Institut für Physik
Accelerating Physics computations with GPUs
at Zoom for now

26 Jan 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Viola Priseman, Max-Planck-Institution , Göttingen, Germany
How can we deal with a pandemic like COVID-19 so that neither health nor society and the economy suffer unnecessarily? We inferred the effectiveness of interventions, and developed effective containment strategies. Interestingly, we have identified a metastable state that not only stabilizes low case numbers, but also significantly reduces the necessary contact reductions and lockdowns. In this talk, we will introduce the underlying models, explore different containment strategies, and discuss recent developments.
at Recording of the presentation

Theorie-Palaver

Institut für Physik

17:30 Uhr s.t., MITP seminar room

Zhengkang (Kevin) Zhang, Caltech
Matching a UV theory onto a low-energy EFT can be efficiently accomplished with functional methods. The functional approach is conceptually appealing: all calculations are performed within the UV theory at the matching scale, and no prior determination of an EFT operator basis is required. In this talk, I will present a simple prescription for functional matching up to one loop order, which accommodates any relativistic UV theory that contains generic interactions among scalar, fermion and vector fields. I will also introduce STrEAM (SuperTrace Evaluation Automated for Matching), a Mathematica package that helps streamline the procedure.
at Zoom

28 Jan 2021

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

Institut für Physik

14 Uhr c.t., None

Univ.-Prof. Dr. Tanja Mehlstäubler, Physikalisch-Technische Bundesanstalt, Braunschweig
Single trapped and laser-cooled ions in Paul traps allow for a high degree of control of atomic quantum systems. They are the basis for modern atomic clocks, quantum computers and quantum simulators. Our research aims to use ion Coulomb crystals, i.e. many-body systems with complex dynamics, for precision spectroscopy. This paves the way to novel quantum clocks for applications such as relativistic geodesy and improved navigation. The high-level of control of self-organized Coulomb crystals also opens up a fascinating insight into the non-equilibrium dynamics of coupled many-body systems, displaying atomic friction and symmetry-breaking phase transitions. We discuss the creation of topological defects in 2D crystals and present recent results on the study of tribology and transport mediated by the topological defect.
at Zoom

29 Jan 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Emanuela Zaccarelli, University of Rome
Microgels are soft particles individually made by cross-linked polymer networks which are nowadays widely used as a colloidal model system because of their swelling properties and their responsivity to external control parameters such temperature or pH. In this talk I will briefly illustrate the protocol that we recently developed to synthesize microgels in-silico, providing a realistic description of the particles. I will then focus on the calculation of their elastic properties and of the effective interactions in bulk and at liquid-liquid interfaces and compare the results with the famous Hertzian model. While we find that the validity of such model in bulk is fairly limited[1], when microgels are adsorbed at interfaces, they effectively behave as 2D elastic disks. Such soft interactions are predicted to show a reentrant liquid-glass-liquid behavior at high densities in a range of experimentally accessible conditions, namely for small and loosely cross-linked microgels[2]. [1] L. Rovigatti, N. Gnan, A. Ninarello and EZ, Macromolecules (2019). [2] F. Camerin, N. Gnan, J. Ruiz-Franco, A. Ninarello, L. Rovigatti and EZ, Phys. Rev. X (2020).

01 Feb 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Asma Hadef, Institut für Physik
Scintillator Material Development for Neutron Reconstruction in DUNE Experiment
at Zoom for now

02 Feb 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Andy Brown, ECMWF, Reading, Great Britain
Accurate weather predictions are of huge value to society, being used to inform actions that save lives and money. They are also a scientific success story, with global 5 day forecasts today being as accurate as 2 days forecasts of 30 years go. This talk will summarize the approach used, recent progress and future research and development priorities. These include further advances in understanding and modelling of multiple components of the Earth system (eg atmopshere, land, ocean and sea-ice), developments in observations and data assimilation methods, and bringing together the physical and computational science communities to take full advantage of new supercomputer architectures and advances in data science.
at Recording of the presentation

Theorie-Palaver

Institut für Physik

14:30 Uhr s.t., None

Anders Eller Thomsen, University of Bern
RG functions are used in QFT to evolve theories between energy scales and are frequently used in both phenomenology and theory. Starting at the 3-loop order, certain RG functions start exhibiting poles in the dimensional expansion, contrasting with the expectation that they should be finite. In this talk, I will clarify how this issue can be understood and how it is linked with an ambiguity in choosing renormalization constants that goes beyond a simple choice of renormalization scheme. The discussion will lead to a preferred prescription for the RG functions, which guarantees finiteness.
at Zoom

03 Feb 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Oleg Tchernyshyov, Johns Hopkins University
https://www.spice.uni-mainz.de/2021/01/13/on-line-seminar-03-february-2021/
at Zoom and SPICE YouTube Channel

04 Feb 2021

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

Institut für Physik

14 Uhr c.t., None

Prof. David Cassidy, University College London, UK
Positronium (Ps) is a hydrogenic atom composed of an electron bound to a positron. Since it contains only leptons Ps is, for all practical purposes, a pure QED system, unaffected by nuclear structure effects. Also, being composed of a particle-antiparticle pair, Ps atoms are metastable, and may decay via self-annihilation, as well as through the usual radiative decay channels seen in regular atoms. The energy levels of Ps can be calculated to arbitrary precision (in principle), and precision spectroscopy of Ps can therefore be used to perform rigorous tests of bound-state QED theory. Moreover, since the theoretical description is limited only by the order of the calculations performed, rather than unknown physical constants or incalculable terms, any observed (and confirmed) disagreement with theory could indicate the existence of “new physics” such as particles or fields not currently included in the Standard Model. In this talk I will describe some new measurements of the Ps n = 2 fine structure, specifically 2 ^3S_1--> 2 ^3P_J (J = 0,1,2) transitions. The experiments were performed using a radioactive isotope-based positron beam coupled to a buffer gas/Penning trap. This allows positron pulses to be generated, which are converted into a dilute Ps gas with in vacuum an initial number density on the order of 10^6 cm^-3. A pulsed dye laser was used to optically excite atoms to the 2 ^3S_1 level, and microwave radiation was used to drive transitions to the 2 ^3P_J levels, which decay radiatively to the ground state before annihilation. The different annihilation decay rates of the ground and excited (S) states allows the fine structure transitions to be monitored via the time spectrum of the Ps annihilation radiation. We found that the measured J = 1 and J = 2 lineshapes exhibited significant asymmetries, whereas a symmetric lineshape was observed for the J = 0 transition. The observed asymmetries are not consistent with the most obvious quantum interference or line-pulling phenomena arising from nearby (off-resonant) transitions, and in the absence of a complete lineshape model we are therefore unable to determine the fine structure intervals for these transtions. Since the J = 0 lineshape did not exhibit any significant asymmetry it was possible to extract a value for the centre frequency: however, the obtained interval was found to disagree with theory by 2.77 MHz, which amounts to 4.5 standard deviations. No mechanism for a line shift of this magnitude has so far been identified.
at Zoom

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau

16:00 Uhr s.t., None

Dr. Johannes Zierenberg, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
Despite decades of research on disease spreading and epidemic outbreaks, the worldwide outbreak of COVID-19 was accompanied by scientific uncertainty resulting in insecure political actions. While scientific knowledge about the disease is initially uncertain until studied in detail, the worldwide available data on infected cases can be used to assess the current stage of the outbreak and allows for short term forecast of potential scenarios. Using a Bayesian framework even allows to incorporate and estimate parameter insecurity. I will present such an approach to infer spreading parameters during the initial outbreak of COVID-19 in Germany, show how to use it for short-term forecasts of potential scenarios, and argue that this approach adds a powerful tool to assist political decision making if the underlying assumptions and limitations are clearly communicated. I will further demonstrate how such models can be used to identify potential weak points in disease control, such as a limited tracing capacity.
at Zoom

05 Feb 2021

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau

10:30 Uhr s.t., None

Lukas Stelzl, Institute of Physics, JGU Mainz
Multi-scale simulations of disordered proteins and their assemblies
at Zoom

08 Feb 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

Sonderseminar: 12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Thomas Honig, Institut für Physik
Higgs Boson Cross Section Measurement in the W-Associated Production and Fully Leptonic Final State at 13 TeV with the ATLAS Experiment"
at Zoom for now

Sonderseminar

SFB/TR49/SFB TRR 173 Spin+X-Kolloquium/TopDyn - Seminar experimentelle Physik der kondensierten Materie

SFB/TR49 - Prof. Dr. Elmers

16:00 Uhr s.t., der Raum wird separat angekündigt

Ulrich Eckern, Augsburg University
Spin-charge conversion and spectral properties of heterostructures containing half-metals: The role of nonquasiparticle states
at Zoom

09 Feb 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Michael Feindt, University of Karlsruhe
This talk will review my personal history as elementary particle physics researcher (having started to work with neural networks at CERN in 1993), professor and entrepreneur (founder of Phi-T (2002) and Blue Yonder(2008)). It was always driven by what today is called Machine Learning and Artificial Intelligence, with emphasis on also predicting and taking advantage from knowledge about uncertainty. Today Blue Yonder, specialized on AI/ML and decision automation in the supply chain from Manufacturing to Retail, has more than 3500 large companies worldwide as customers and has delivered more than 1 trillion predictions. Examples from many different areas (physics, insurance, retail, supply chain) and experience gained over many years will show the tremendous value, but also the difficulties in bringing these methods into real life production in large scale international collaborations and companies - often against resistance.
at Recording of the presentation

Theorie-Palaver

Institut für Physik

14:30 Uhr s.t., MITP seminar room

Riccardo Barbieri, SNS Pisa
Motivated by the hierarchy problem and by the pattern of quark masses and mixings, I describe a picture of flavour physics that should give rise in a not too distant future to observable deviations from the SM in Higgs compositeness and/or in B-decays (if LFV confirmed) or perhaps even in supersymmetry, depending on the specific realization.
at Zoom

10 Feb 2021

PRISMA Colloquium

Institut für Physik

13:00 Uhr s.t., None

Nicola Neri, Università di Milano
Magnetic and electric dipole moments of fundamental particles provide powerful probes for physics within and beyond the Standard Model. For the case of short-lived particles these have not been experimentally accessible to date due to the difficulties imposed by their short lifetimes. A unique program of direct measurements of electromagnetic dipole moments of strange and charm baryons, and ultimately beauty baryons and the tau lepton, at the LHC is proposed. Novel experimental techniques have been developed, along with feasibility studies and projected sensitivities for different luminosity scenarios.
at Zoom

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Claudia Felser, MPI Chemical Physics of Solids
Magnetic Materials and Topology
at Zoom and SPICE YouTube Channel

11 Feb 2021

Theoriekolloquium

Die Dozierenden der Theoretischen Physik

16:00 Uhr s.t., usually Newton-Raum, Staudinger Weg 9, 01-122

Ehud Altman, UC Berkeley
From physics journals to campaign rallies, in this talk I'll try to explain what drives the remarkable popularity of the Sachdev-Ye-Kitaev model. In the first part I'll survey the evolution of this system from its origins as a solvable toy model of strongly interacting electrons to its current fame as a toy model of a quantum black hole. The latter came with Kitaev's discovery that, like a black hole, the low temperature dynamics of this model saturates the quantum bound on chaos. In the second part of the talk I will discuss how the model can be liberated from its status as a toy model by generalizing the physics from zero spatial dimensions to a genuine higher dimensional field theory. Time permitting I will discuss a specific application of such a field theory to describe unconventional quantum criticality in correlated electron systems.
at Zoom

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

Institut für Physik

14 Uhr c.t., None

Dr. Stefan Ulmer, Ulmer Fundamental Symmetries Laboratory, RIKEN, Japan & CERN
The Standard Model of particle physics is both incredibly successful and glaringly incomplete. Among the questions left open is the striking imbalance of matter and antimatter in our universe, which inspires experiments to compare the fundamental properties of matter/antimatter conjugates with high precision. The BASE collaboration at the antiproton decelerator of CERN is performing such high-precision comparisons with protons and antiprotons. Using advanced, ultra-stable, cryogenic particle traps and superconducting detectors with single particle sensitivity, we have performed the most precise measurement of the proton-to-antiproton charge-to-mass ratio with a fractional uncertainty of 69 parts per trillion [1]. In another measurement, we have invented a novel spectroscopy method, which allowed for the first ultra-high precision measurement of the antiproton magnetic moment with a fractional precision of 1.5 parts in a billion [2]. Together with our recent measurement of the proton magnetic moment [3] this improves the precision of previous experiments [4] by more than a factor of 3000. A time series analysis of this recent magnetic moment measurement furthermore enabled us to set first direct constraints on the interaction of antiprotons with axion-like particles (ALPs) [5], and most recently, we have used our ultra-sensitive single particle detection systems to derive narrow-band constraints on the conversion of ALPs into photons [6]. In my talk I will review the recent achievements of BASE and will outline strategies to further improve our high-precision studies of matter-antimatter symmetry. This outlook will involve the implementation of sympathetic cooling of antiprotons using quantum logic methods, the development of the transportable antiproton trap BASE-STEP, and will also review recent experimental progress towards 10-fold improved measurements of the antiproton properties. [1] S. Ulmer et al., Nature 524, 196 (2015). [2] C. Smorra et al., Nature 550, 371 (2017). [3] G. Schneider et al., Science 358, 1081 (2017). [4] J. DiSciacca et al., Phys. Rev. Lett. 110, 130801 (2013). [5] C. Smorra et al., Nature 575, 310 (2019). [6] J. A. Devlin et al., Phys. Rev. Lett., accepted (2021). S. Ulmer1, K. Blaum2, M. Bohman1,2, M. Borchert1,3, J. A. Devlin1,4, S. Erlewein1,2,4, M. Fleck1,5, C. Smorra1, M. Wiesinger1,2, C. Will2, E. Wursten5, Y. Matsuda6, C. Ospelkaus3, W. Quint6, J. Walz7,8, Y. Yamazaki1 1RIKEN, Ulmer Fundamental Symmetries Laboratory, Saitama, Japan; 2Max-Planck-Institut für Kernphysik, Heidelberg, Germany; 3Leibnitz University, Hannover, Germany; 4CERN, Geneva, Switzerland; 5The University of Tokyo, Tokyo, Japan; 6GSI - Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany; 7Johannes Gutenberg-Universität, Mainz, Germany; 8Helmholtz-Institut Mainz, Germany;
at Zoom

12 Feb 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Jens-Uwe Sommer, Leibniz-Institute of Polymer Research Dresden and TU Dresden
The lower critical solution temperature (LCST) transition is introduced as type-II transition which results in many cases from competing effects of hydrogen bonding and hydrophobic behaviour of water-soluble polymers such as PEO and PNIPAm. As a consequence of the new type of phase separation a switch-like temperature response and phase coexistence is predicted for immobilized polymers such as polymer brushes or gels. I will give an introduction to simple theoretical concepts related with the type-II transition. Furthermore, I will demonstrate that mixed solvents can lead to type-II transitions with the prominent example of so-called co-nonsolvency [1]. Computer simulations and experiments confirm the basic conclusions from the theoretical model for polymer brushes [2,3]. Moreover, this phase transition is most likely driving the formation of protein-RNA-droplets in living cells. Using atomistic simulations it is shown for the example of PEO that stretching of the conformations can induce a phase transition far below the LCST which can be explained by the release of hydrogen bonds in the stretched state of PEO [4]. An aquamelt is introduced in general as a system where stretching/flow induces phase separation and subsquent crystallization, very similar to the process of spider-silk spinning in Nature. Aquamelts break the paradigm that solution properties of polymers are independent of conformation statistics. [1]J.-U. Sommer, Gluonic and Regulatory Solvents: A Paradigm for Tunable Phase Segregation in Polymers, Macromolecules 51, 3066 (2018); Adsorption-Attraction Model for Co-Nonsolvency in Polymer Brushes, Macromolecules 50, 2219 (2017) [2]A. Galuschko and J.-U. Sommer, Co-Nonsolvency Response of a Polymer Brush: A Molecular Dynamics Study, Macromolecules 52, 4120 (2019) [3]H. Yong, E. Bittrich, P. Uhlmann, A. Fery and J.-U. Sommer, Co-nonsolvency transition of poly(N-isopropylacrylamide) brushes in a series of binary mixtures, Macromolecules 52, 6285 (2019) [4]S. Donnets and J.-U. Sommer, J. Phys. Chem. B 122, 392 (2018)

Link: https://zoom.us/j/98197416231?pwd=c3ZnV0V6TDhsbkkwMnVDbTVWRG41dz09

16 Feb 2021

Theorie-Palaver

Institut für Physik

14:30 Uhr s.t., MITP seminar room

Nick Evans, Southampton U.
I review arguments that chiral symmetry breaking is triggered when the quark bilinear condensate's dimension passes through one. This is supported by gap equations and more recently holographic models. Confinement may then be a separate property of the pure Yang-Mills theory below the scale of the dynamically generated quark mass, occurring at the scale of the pole in the deep IR running. Theories with more than one representation may have gaps between the condensation scales for the different representations with confinement below the lowest scale. Here, we use perturbative results for the running of the gauge coupling and gamma in asymptotically free SU(Nc) gauge theories with matter in higher dimension representations to seek the best candidate theories where confinement and chiral symmetry breaking can be maximally separated.
at Zoom

17 Feb 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Olena Gomonay, JGU
Seeing or listening: magnetoelastic effects in antiferromagnetic textures
at Zoom and SPICE YouTube Channel

19 Feb 2021

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau

10:30 Uhr s.t., None

Adam Sieradzan, University of Gdańsk, Poland
UNICORN: UNIfied COarse-gRaiNed model of biological macromolecules
at Zoom

24 Feb 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Sergej Demokritov, University of Münster
Spatio-Temporal Dynamics of Magnon Bose-Einstein Condensates
at Zoom and SPICE YouTube Channel

26 Feb 2021

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau

18:00 Uhr s.t., None

Marina Guenza, Dept. of Chemistry and Biochemistry, University of Oregon, USA
The Integral Equation Theory of Coarse-Graining (IECG) and its applications.
at zoom

03 Mar 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Ulrich Rößler, IFW Dresden
Improper Dyzaloshinskii spirals and metamagnetic textures - and where to look for them
at Zoom and SPICE YouTube Channel

05 Mar 2021

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau

14:00 Uhr s.t., None

Frank Siebers, Institute of Physics, JGU
Dynamics of Light Driven Circle Walkers
at Zoom

Master Colloquium

10 Mar 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Theo Rasing, Radboud University
All-optical control of magnetism: from fundamentals to brain-inspired computing concepts
at Zoom and SPICE YouTube Channel

17 Mar 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Henning Sirringhaus, University of Cambridge
Charge and Spin transport physics of organic semiconductors
at Zoom and SPICE YouTube Channel

24 Mar 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Christian Back, TUM
Optical and Electrical Detection of Spin-Orbit Fields
at Zoom and SPICE YouTube Channel

31 Mar 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Igor Mazin, George Mason University
Dynamic generation of scalar chirality and topological Hall effect in spiral magnets
at Zoom and SPICE YouTube Channel

07 Apr 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Silvia Viola-Kusminskiy, MPL
Quantum magnonics: Quantum optics with magnons
at Zoom and SPICE YouTube Channel

12 Apr 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Timo Graffe, Universität Mainz
Schüler Labor "Climate Escape" (in German)
at Zoom for now

13 Apr 2021

Theorie-Palaver

Institut für Physik

14:30 Uhr s.t., MITP seminar room

Raffaele Tito D'Agnolo, IPhT Saclay
I will discuss settings where the Higgs mass squared affects the vacuum expectation value of local operators and can thus act as a “trigger” of new cosmological dynamics. This triggering mechanism underlies several existing solutions to the hierarchy problem that trace the origin of the weak scale to the early history of the Universe. Thinking about these solutions more systematically from the point of view of weak scale triggers allows to understand their common predictions, to find new solutions and to identify unexpected physics related to naturalness in a rather model-independent way. As an example I discuss a BSM trigger in a Two Higgs Doublet Model and show how it can be used to link the tuning of the Higgs mass to that of the cosmological constant. This weak scale trigger demands the existence of new Higgs states necessarily comparable to or lighter than the weak scale, with no wiggle room to decouple them.
at Zoom

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Hartmut Wittig und Martin Fertl, University of Mainz
The long-persisting discrepancy between the Standard Model prediction of the anomalous magnetic moment of the muon (aµ) and its latest measurement provides an intriguing hint to new physics. Since 2017, the Muon g − 2 Theory Initiative has assessed the theoretical prediction for aµ, focusing on the contributions from the strong interaction, which account for the dominant part of the uncertainty. The latest estimate for the Standard Model prediction, which was published in a recent White Paper, has failed to resolve the discrepancy with the experimental measurement at Brookhaven National Laboratory, which stands at 3.7 standard deviations. At Fermi National Accelerator Laboratory, USA, the Muon g-2 collaboration is performing a new measurement of aµ aiming at an ultimately fourfold smaller uncertainty than achieved with the predecessor experiment. To extract the value of aµ a clock comparison experiment is performed with spin-polarized muons confined in a superbly controlled electric and magnetic field environment. The deviation of the Larmor from the cyclotron frequency, the anomalous spin precession frequency, is determined while a high-precision measurement of the magnetic field environment is performed using nuclear magnetic resonance techniques. We will provide an introduction to the current theory prediction before we will present and discuss the first results of the FNAL experiment from its 2018 science run.
at Recording of the presentation

14 Apr 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., None

Thomas Speck, Johannes Gutenberg University
TBA
at Zoom

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Jörg Wunderlich, Regensburg University
Magneto-Seebeck microscopy of spin-orbit-torque driven domain wall motion in a collinear antiferromagnet
at Zoom and SPICE YouTube Channel

︾

aktuell

15 Apr 2021

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

Institut für Physik

14:00 Uhr s.t., None

Prof. Dr. Peter Hommelhoff, Friedrich-Alexander-Universität Erlangen-Nürnberg
Free electrons are used in a plethora of instruments, ranging from electron microscopes to particle accelerators and modern light sources for decades. Yet, fundamentally new concepts are surfacing, taking advantage of electrons in an entirely new way, mainly based on quantum mechanical and nanophotonics concepts. In this talk, I will show recent results towards interaction-lean imaging with electrons and on-chip control of electrons. These results bring us closer to a quantum electron microscope and to a particle accelerator on a chip.
at Zoom

︾
zukünftige Termine
19 Apr 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Vincent Roy, Universität Mainz
The Story of the Mainz Neutrino Mass Experiment
at Zoom for now

SFB/TR49/SFB TRR 173 Spin+X-Kolloquium/TopDyn - Seminar experimentelle Physik der kondensierten Materie

SFB/TR49 - Prof. Dr. Elmers

16:00 Uhr s.t., None

Andrii Chumak, University of Vienna, Austria
Nano-Magnonics: From Room to Cryogenic Temperatures
at Zoom

20 Apr 2021

Theorie-Palaver

Institut für Physik

14:30 Uhr s.t., MITP seminar room

Xiaofeng Xu, Bern University
Canonical Feynman integrals are of great interest in the study of scattering amplitudes at the multi-loop level. We propose to construct d log-form integrals of the hypergeometric type, treat them as a representation of Feynman integrals, and project them into master integrals using intersection theory. This provides a constructive way to build canonical master integrals whose differential equations can be solved easily. We use our method to investigate both the maximally cut integrals and the uncut ones at one and two loops, and demonstrate its applicability in problems with multiple scales.
at Zoom

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Mehran Kardar, Massachusetts Institute of Technology, Cambridge, USA
Affinity maturation (AM) is the process through which the immune system evolves antibodies (Abs) which efficiently bind to antigens (Ags), e.g. to spikes on the surface of a virus. This process involves competition between B-cells: those that ingest more Ags receive signals (from T helper cells) to replicate and mutate for another round of competition. Modeling this process, we find that the affinity of the resulting Abs is a non-monotonic function of the target (e.g. viral spike) density, with the strongest binding at an intermediate density (set by the two-arm structure of the antibody). We argue that, to evade the immune system, most viruses evolve high spike densities (SDs). An exception is HIV whose SD is two orders of magnitude lower than other viruses. However, HIV also interferes with AM by depleting T helper cells, a key component of Ab evolution. We find that T helper cell depletion results in high affinity antibodies when SD is high, but not if SD is low. This special feature of HIV infection may have led to the evolution of a low SD to avoid potent immune responses early on in infection. Our modeling also provides guides for design of vaccination strategies against rapidly mutating viruses.
at Zoom

21 Apr 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Angelika Kühnle, Bielefeld University
TBA

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Chiara Ciccarelli, University of Cambridge
tba
at Zoom and SPICE YouTube Channel

22 Apr 2021

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

Institut für Physik

14:00 Uhr s.t., None

Prof. Dr. Konrad Lehnert, JILA, University of Colorado, Boulder, USA
Can emerging quantum information technologies, in some way, improve or enhance searches for fundamental physical phenomena? Indeed, the use of optical squeezing in gravitational wave observatories is a beautiful example that they can. In addition to this one prominent example, the search for dark matter may offer several other near-term experiments that can, and perhaps must, use enhanced quantum sensing methods. In particular detail, I’ll discuss the case of searching for a hypothetical dark matter particle known as the axion and accelerating the search using quantum squeezing approaches.
at Zoom

26 Apr 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Jan Weldert, Universität Mainz
Event reconstruction using likelihood-free inference
at Zoom for now

27 Apr 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Jason Detwiler, University of Washington, USA
Neutrinos are known for their elusive nature due to their extremely small cross section for scattering off of individual nucleons inside of nuclei. However they can also undergo billiard-ball-like coherent elastic scattering off of entire nuclei, with a greatly enhanced cross section. This coherent elastic neutrino-nucleus scattering (CEvNS) is an important process in core-collapse supernovae, and can also be used for astrophysical and terrestrial neutrino detection. The coherence of the interaction can also amplify potential non-standard interactions between neutrinos and quarks, making it an ideal mode for testing as-yet unprobed physics beyond the Standard Model. Although CEvNS was predicted in 1974, its first observation was only recently made in 2017 by the COHERENT collaboration, leveraging decades of Dark Matter detector R&D that has yielded technologies with sufficient sensitivity to observe the ultra-faint nuclear recoils that are the only signatures of the interaction's occurrence. COHERENT's discovery was also enabled by its nearly ideal pulsed source of pion-decay neutrinos: the beam dump of the Spallation Neutron Source at Oak Ridge National Laboratory. In this talk, I will discuss the physics of CEvNS and its challenging measurement. I'll describe COHERENT's first observation of CEvNS using the world's first hand-held neutrino detector, a CsI scintillating crystal. I will then detail our more recent first observation of CEvNS with argon using a scintillating volume of liquid Ar, including our updated sensitivity to non-standard neutrino interactions and other physics. I'll also describe our plans to field two more detectors using NaI scintillating crystals as well as an array of germanium radiation detectors, and our longer term plans to build multiple ton-scale experiments at a new beam stop with significantly improved sensitivity.
at Zoom

28 Apr 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Ulrich Nowak, University of Konstanz
Spin dynamics: the Landau-Lifshitz equation and beyond
at Zoom and SPICE YouTube Channel

PRISMA Colloquium

Institut für Physik

13:00 Uhr s.t., None

Javier Fuentes, JGU
Flavor anomalies in B decays
at Zoom

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Pol Besenius, Johannes Gutenberg University
TBA

29 Apr 2021

Theoriekolloquium

Die Dozierenden der Theoretischen Physik

16:00 Uhr s.t., None

Joaquin Rodriguez-Nieva, Stanford University
TBA Topic: Th. Kolloquium Time: Apr 29, 2021 04:00 PM Amsterdam, Berlin, Rome, Stockholm, Vienna Join Zoom Meeting https://zoom.us/j/95899860316?pwd=dHBiREgyNnBOUml3QzNBSzUxZGJmQT09 Meeting ID: 958 9986 0316 Passcode: 090910
at Zoom

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

Institut für Physik

14:00 Uhr s.t., None

Prof. Dr. Andreas Hemmerich, Institut für Laser-Physik, Universität Hamburg
I will review our recent research on time crystal dynamics in an atom-cavity system. In contrast to discrete time crystals in driven closed systems, where dissipation constitutes an undesired obstacle, I will discuss an ansatz, where tailored dissipation and fluctuations, induced via controlled coupling to a suitable environment, stabilize time crystal dynamics. The central signature in our implementation in a driven open atom-cavity system is a period doubled switching between distinct chequerboard density wave patterns, induced by the interplay between controlled cavity-dissipation, cavity-mediated interactions and external driving. We demonstrate the robustness of this dynamical phase against system parameter changes and temporal perturbations of the driving.
at Zoom

04 May 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Gia Dvali, Max Plank Institute of Physics, Munich
Understanding the origin of hierarchies is one of the main driving forces of today's fundamental research. The well-known examples are provided by the hierarchy between the weak and Planck scales, the hierarchy between neutrino and electron masses and the hierarchy between the Planck scale and the vacuum energy of the present Universe. Sometimes these puzzles are classified as so-called ``naturalness problems". Historically, in the case of proton/pion mass hierarchy, such questions led to advances that changed modern particle physics. In this talk we review certain representative examples when the hierarchy can be taken as a serious indication for new physics. We also review cases when a seeming naturalness problem is nullified by consistency of the theory. We give an example of the celebrated naturalness puzzle of the cosmological term. This however turns out to be fictitious, since the consistency of the S-matrix formulation demands that the cosmological constant is excluded from the energy budget of our Universe.
at Zoom

05 May 2021

SPICE-Spin+X Seminar

TUK and JGU

15:00 Uhr s.t., None

Sangeeta Sharma, Max-Born-Institute
Ultrafast coupled charge, spin and nuclear dynamics: ab-initio
at Zoom and SPICE YouTube Channel

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Markus Mezger, University of Vienna, MPI-P
TBA

06 May 2021

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

Institut für Physik

14:00 Uhr s.t., None

Prof. Dr. Ignacio Cirac, Max-Planck-Institut für Quantenoptik, Garching
Quantum many-body systems are very hard to simulate, as computational resources (time and memory) typically grow exponentially with system size. However, quantum computers or analog quantum simulators may perform that task in a much more efficient way. In this talk, I will first review some of the quantum algorithms that have been proposed for this task and then explain the advantages and disadvantages of analog quantum simulators. I will also describe theoretical proposals to solve different quantum simulation problems with cold atoms in optical lattices.
at Zoom

11 May 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Achim Stahl, RWTH Aachen, Germany
News from the Einstein-Telescope
at Zoom

12 May 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Michael Kappl, MPI-Polymer Research
TBA

18 May 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Kathrin Valerius, Karlsruher Institute of Technology, Germany
News on the Neutrino-Mass Measurement
at Zoom

19 May 2021

PRISMA Colloquium

Institut für Physik

13:00 Uhr s.t., None

Iwona Grabowska-Bold, Krakow
Heavy Ion Physics at the LHC
at Zoom

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Kurt Kremer, MPI-Polymer Research
TBA

20 May 2021

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

Institut für Physik

14:00 Uhr s.t., None

Prof. Dr. Ralf Röhlsberger, Helmholtz Institut Jena/Friedrich-Schiller Universität Jena
TBA
at Zoom

26 May 2021

PRISMA Colloquium

Institut für Physik

13:00 Uhr s.t., None

Gilad Perez, Weizmann Institute
Beyond standard model theory in AMO
at Zoom

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Arash Nikoubashman, Johannes Gutenberg University
TBA

27 May 2021

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

Institut für Physik

14:00 Uhr s.t., None

Dr. Christian Sanner, JILA, University of Colorado, Boulder, USA
Can Fermi quantum statistics be used to manipulate the radiative properties of atomic emitters? Is it possible to extend the natural lifetime of an electronically excited atom by placing it inside a bath of quantum-degenerate ground-state atoms? I will report on an experiment that demonstrates how a Fermi sea can block the spontaneous decay of an excited atom. This striking manifestation of Fermi statistics connects for the first time the fundamental radiative property of atoms to their motional degrees of freedom subject to quantum statistics. Quantum engineering the atom-photon coupling opens up new perspectives for optical clocks, which face spontaneous decay as a fundamental decoherence mechanism.
at Zoom

01 Jun 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Katia Parodi, University of Munich, Germany
High Precision Ion Therapy
at Zoom

02 Jun 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Nathalie Katsonis, University of Groningen, The Netherlands
TBA

03 Jun 2021

Theoriekolloquium

Die Dozierenden der Theoretischen Physik

16:00 Uhr s.t., Newton-Raum, Staudinger Weg 9, 01-122

Javier Argüello Luengo, ICFO
TBA Topic: Th. Kolloquium Time: Jun 3, 2021 04:00 PM Amsterdam, Berlin, Rome, Stockholm, Vienna Join Zoom Meeting https://zoom.us/j/95333368894?pwd=bitvZWVmSE15MGNydmFKbitxSE5qQT09 Meeting ID: 953 3336 8894 Passcode: 090910
at Zoom

08 Jun 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Jens Erler, University of Mainz
Half a century ago the foundations underpinning the gauge theories of the strong, weak and electromagnetic interactions had been laid out, and the age of precision calculations for its tests and the determination of its parameters could begin. We recall some of the history with an emphasis on the role played by electroweak precision tests. While in the past theoretical ideas have often preceded experimental discoveries, the years and decades ahead of us are in desperate need of experimental guidance.
at Zoom

09 Jun 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Regine von Klitzing, Technical University of Darmstadt
TBA

10 Jun 2021

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

Institut für Physik

14:00 Uhr s.t., None

Dr. Ana Maria Rey, JILA, NIST and University of Colorado, Boulder, USA
I will discuss recent progress on the use of planar crystals with hundreds of ions as a platform for quantum simulation of spin and spin-boson models. The key idea is the use of a pair of lasers to couple two internal levels of the ions, that act as a spin½ degree of freedom, to the vibrational modes, phonons, of the crystal. In the regime when phonons do not play an active role in the dynamics and instead mediate spin-spin interactions we have been able to simulate Ising models with tunable-range spin couplings, and a many-body echo sequence, which we used to measure out-of-time-order correlations (OTOCs), a type of correlations that quantify the scrambling of quantum information across the system’s many-body degrees of freedom. In the regime when phonons actively participate we have been able to simulate the Dicke model, an iconic model in quantum optics which describes the coupling of a (large) spin to an oscillator and more recently realize a many-body quantum-enhanced sensor that can detect weak displacements and electric fields. Our system is the first to demonstrate an enhanced sensitivity resulting from quantum entanglement in a mesoscopic ion crystal with an improvement by a factor of 300 over prior classical protocols in trapped ions and more than an order of magnitude compared to state-of-the-art electrometers based on Rydberg atoms. Overall my talk plans to illustrate the great potential offered by trapped ion crystals not only as quantum simulators but also as feasible near-term detectors of dark matter.
at Zoom

15 Jun 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Helmut Satz, University of Bielefeld, Germany
The Statistical Mechanics of Bird Swarms
at Zoom

16 Jun 2021

PRISMA Colloquium

Institut für Physik

13:00 Uhr s.t., None

Matteo Cadeddu, INFN Cagliari
Coherent elastic neutrino scattering and constraints for the neutron skin
at Zoom

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Sigi Waldvogel, Johannes Gutenberg University
TBA

17 Jun 2021

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

Institut für Physik

14:00 Uhr s.t., None

Dr. Silvia Viola-Kusminskiy, Max-Planck-Institute for the Science of Light, Erlangen
TBA
at Zoom

21 Jun 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Quirin Weitzel and Steffen Schönfelder, Prisma Detector Lab
3D-Printing Technologies and Possibilities in the PRISMA Detector Lab
at Zoom for now

SFB/TR49/SFB TRR 173 Spin+X-Kolloquium/TopDyn - Seminar experimentelle Physik der kondensierten Materie

SFB/TR49 - Prof. Dr. Elmers

16:00 Uhr s.t., None

Felix Tuczek, Christian-Albrechts-Universität zu Kiel
Spin-state switching of iron complexes adsorbed on surfaces
at Zoom

22 Jun 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Horst Geckeis, Karlsruher Institute of Technology, Germany
Endlagerstätten in Deutschland
at Zoom

23 Jun 2021

PRISMA Colloquium

Institut für Physik

17:00 Uhr s.t., None

Svetlana Barkanova, Memorial University
please note different time!
at Zoom

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Hans-Jürgen Butt, MPI-Polymer Research
TBA

24 Jun 2021

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

Institut für Physik

14:00 Uhr s.t., None

Prof. Dr. Georg von Freymann, Technische Universität Kaiserslautern
Terahertz spectroscopy has evolved over recent years from an interesting but technologically hard to address tool for fundamental studies to a technology with industrial applications. Closing the so-called terahertz gap is nowadays possible with ultrafast lasers from the optical side as well as with millimeter-wave-technology from the electronic side. After a brief review of the state-of-the-art I will focus on recent progress on terahertz cross-correlation-spectroscopy driven by a superluminescent light emitting diode and terahertz spectroscopy with undetected photons for which all terahertz spectral information is gained from visible photons.
at Zoom

28 Jun 2021

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik

12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum

Christian Matthé, Universität Mainz
Wire detector for atomic hydrogen beam monitoring
at Zoom for now

29 Jun 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Norbert M. Linke, Joint Quantum Institute and Department of Physics, University of Maryland, College Park, MD 20742, USA
Trapped ions give us a high degree of detailed control of their various quantum degrees of freedom, which has enabled a large number of experiments in quantum optics, quantum computing, simulation and networking as well as precision metrology and others. We present a quantum architecture consisting of a linear chain of trapped 171 Yb+ ions with individual laser beam addressing and readout. The collective modes of motion in the chain are used to efficiently produce entangling gates between any qubit pair. In combination with a classical software stack, this becomes in effect an arbitrarily programmable fully connected quantum computer. Over the past five years, we have employed this experiment to demonstrate a variety of quantum algorithms with the help of a community of academic partners, including cross-hardware comparisons with commercially developed systems and digital quantum simulations of models from high-energy physics and other areas. We also use the same level of control to study interesting quantum phenomena using the motional degrees of freedom directly, such as exotic para particles and Hubbard models of phonons. This talk will give recent highlights from both of these approaches and discuss improvements in trap technology for scaling up as well as other ideas for the future.
at Zoom

30 Jun 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Jens-Uwe Sommers, Leibniz Institute of Polymer Research, Dresden
TBA

01 Jul 2021

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

Institut für Physik

14:00 Uhr s.t., None

Dr. Sven Herrmann, ZARM, Universität Bremen
TBA
at Zoom

06 Jul 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Ken Carslaw, University of Leeds, Great Britain
Ice nucleation and its effect on the sensitivity of Earth´s climate
at Zoom

07 Jul 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Sebastian Seiffert, Johannes Gutenberg University
TBA

08 Jul 2021

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

Institut für Physik

14:00 Uhr s.t., None

Prof. Dr. Hiroshi Kawarada, School of Fundamental Science and Engineering, Waseda University, Japan
TBA
at Zoom

13 Jul 2021

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar

16:15 Uhr s.t., None

Nick Hutzler, Caltech, Californian Institute of Technology, USA
The fact that the universe is made entirely out of matter, and contains no free anti-matter, has no physical explanation. The unknown process that created matter in the universe must violate a number of fundamental symmetries, including those that forbid the existence of certain electromagnetic moments of fundamental particles whose signatures are amplified by the large internal fields in polar molecules. We discuss spectroscopic and theoretical investigations into polyatomic molecules that uniquely combine multiple desirable features for precision measurement, such as high polarizability through symmetry-lowering mechanical motions, novel electronic and bonding structures, laser cooling, and exotic nuclei.
at Zoom

14 Jul 2021

GRK 2516 Soft Matter Seminar

Uni Mainz

10:30 Uhr s.t., via Zoom

Friederike Schmid, Johannes Gutenberg University
TBA

15 Jul 2021

Theoriekolloquium

Die Dozierenden der Theoretischen Physik

16:00 Uhr s.t., Newton-Raum, Staudinger Weg 9, 01-122

Francesco Piazza, MPIPKS - Dresden
TBA Topic: Th. Kolloq. Time: Jul 15, 2021 04:00 PM Amsterdam, Berlin, Rome, Stockholm, Vienna Join Zoom Meeting https://zoom.us/j/94666378028?pwd=OThVejk4bHF6WkhQRU9LaWV2VWNzUT09 Meeting ID: 946 6637 8028 Passcode: 090910
at Zoom

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

Institut für Physik

14:00 Uhr s.t., None

Prof. Dr. Stefan Filipp, Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften
The rapid development of quantum technologies in the recent past has brought us a step closer to operational quantum computers that hold promise to outperform conventional computers in certain types of problems. While a large number of qubits is necessary to run complex algorithms, fast and high-fidelity gate operations of different types are as important. We utilize a system based on fixed-frequency superconducting qubits that are characterized by their stability, relatively long coherence times and scalability. On this platform we explore different ways to increase the performance of future quantum processors. We demonstrate that optimal control techniques allow us to shape microwave control pulses and realize fast single-qubit pulses without sacrificing their fidelity. Furthermore, we explore measurement techniques with a high duty cycle to overcome the challenge of time-consuming optimization sequences. For the generation of entangled two-qubit states we make use of a parametrically driven tunable coupler and implement different types of gates. Since exchange-type gates preserve the number of qubit excitations these are particularly well suited for quantum chemistry algorithms in which the number of electrons in the molecule is typically fixed. With this choice of gates we can make best use of the available hardware and realize short algorithms that finish within the coherence time of the system. With gate fidelities around 95% we compute the eigenstates within an accuracy of 50 mHartree on average, a good starting point for near-term applications with scientific and commercial relevance.
at Zoom