Semesterübersicht Wintersemester 2019/2020
Wintersemester 2019/2020  Sommersemester 2020  Wintersemester 2020/2021
Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik Sonderseminar: 14:15 Uhr s.t., HS Kernphysik, Becherweg 45 
Garth Huber, University of Regina, Regina, Saskatchewan, Canada  
see attached pdf  
Sonderseminar  

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., Newtonraum, 01122, Staudingerweg 9 
Christoph Ortner, University of Warwick  
Accurate molecular simulation requires computationally expensive quantum chemistry models that makes simulating complex material phenomena or large molecules intractable. The past decade has seen a revival of interatomic potentials (IPs), fast but traditionally inaccurate surrogate models, recasting their construction as an approximation and datafitting problem.
I will give an introduction to this problem, from a mixed modelling / data / mathematics perspective. In particular I want to show how it can be formalised as a highdimensional approximation problem, with many structures that can be exploited to make it tractable. I will introduce two approximation schemes, both using different symmetric polynomials, targeting in particular efficiency and transferability, some preliminary simulation results, and the beginnings of a rigorous numerical analysis.
Joint work with Geneviève Dusson (CNRS Besançon), Markus Bachmayr (Mainz), Gabor Csanyi and Cas van der Oord (Cambridge), Simon Etter (NU Singapur).  

Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 11:15 Uhr s.t., Newtonraum, 01122, Staudingerweg 9 
Genevive Dusson, University of Warwick  
I will present the practical construction of interatomic potentials for materials and molecules based on a bodyorder expansion (ANOVA, HDRM), each body order being represented by polynomials satisfying the rotation and permutation symmetry of the "exact" potential energy surface. These polynomials are determined in a datadriven fashion from linear fits trained with ab initio data.
I will report convergence tests on training sets for materials and molecules, illustrating the accuracy, the low computational cost, and the systematic improvability of the potential. I will then outline a range of the regularisation procedures that we incorporate into the polynomial fits to achieve transferability of the potentials. Finally, I will outline a testing framework to stresstest the generalisation capabilities of new potentials far from the training set.
Joint work with Alice Allen (Cambridge), Gbor Csnyi (Cambridge), Christoph Ortner (Warwick), and Cas van der Oord (Cambridge).  

TheoriePalaver
Institut für Physik 14:30 Uhr s.t., Socialroom 
Fatemeh Elahi, IPM, Tehran  
A few hundred cold gas clouds were recently discovered, each situated a few hundred parsecs from the center of the Milky Way Galaxy. These gas clouds can provide unprecedented sensitivity to dark matterstandard model interactions. The main physical basis is simple: dark matter tends to have a higher temperature than the coldest interstellar and intergalactic gas. Therefore, dark matter can heat the gas to higherthanobserved temperatures, if dark matter interacts enough with baryons or electrons in the gas cloud. In this talk, I will discuss the bounds cold gas clouds give on ultralight dark photon, vector portal, and millicharged dark matter.  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Wick Haxton, Department of Physics, Berkeley  
There is a great deal of experimental effort being invested in laboratory searches for heavy dark matter particles, where the signal is a recoiling nucleus produce by dark matter elastic scattering. An interesting question is the number of experiments that will need to be done to ensure that the available discovery space has been adequately covered. Post discovery, a related question will be the number of independent experiment that will need to be completed, to fully characterize the interaction. I will describe an approach based on effective theory that allows one to address these and other questions.  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Dr. John M. Schwantes, Pacific Northwest National Laboratory , Richland, WA, USA  
The young science of nuclear forensics was born out of a response to discoveries of weaponsusable nuclear Materials Out of Regulatory Control (MORC) in northern Europe in the early 1990s. This science not only supports law enforcement response to MORC events but represents a key component of nuclear security for any nation with nuclear or radiological materials holdings. Since the birth of nuclear forensic science, efforts like the Nuclear Security Summit, the Global Initiative to Combat Nuclear Terrorism, as well as those by the International Atomic Energy Agency and the Nuclear Forensics International Technical Working Group have strengthened nuclear forensics capabilities worldwide. Here, the capabilities and limitations of nuclear forensic science are described and several examples of applications of nuclear forensics in support of emergency response, law enforcement, and national security are provided.  

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
J. Diefenbach, Mainz  
Strahlenschutzunterweisung Kernphysik  

TheoriePalaver
Institut für Physik 14:30 Uhr s.t., MITP seminar room 
Andreas Helset, Bohr Institute  
We formulate an effective field theory describing large mass scalars and fermions minimally coupled to gravity. The operators of this effective field theory are organized in powers of the transfer momentum divided by the mass of the matter field, an expansion which lends itself to the efficient extraction of classical contributions from loop amplitudes in both the postNewtonian and postMinkowskian regimes. We use this effective field theory to calculate the classical and leading quantum gravitational scattering amplitude of two heavy spin1/2 particles at the second postMinkowskian order.  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Andreas Burkert, Faculty of Physics, LMU Munich  
Disk Galaxies: Our Fascinating Cosmic Habitats  

Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 10:15 Uhr s.t., Newtonraum, 01122, Staudingerweg 9 
Joerg Steinkamp, ZDV, Uni Mainz  
Research data management and data archiving at ZDV/JGU with iRODS  

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
O. Javier Hernandez, Mainz  
Nuclear structure corrections in muonic deuterium  

Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
Michael Goedel, Institut für Physik  
Track reconstruction in Project 8  
Masterkolloqium 
TheoriePalaver
Institut für Physik 14:30 Uhr s.t., MITP seminar room 
Alexey Vladimirov, Regensburg University  
The evolution of transverse momentum dependent distributions or TMDevolution differs from ordinary renormalization group evolution in several aspects. Two main ones are its doublescale nature and the presence of nonperturbative component. In the talk, I review the recent progress in studies of TMDevolution, including the proof of rapiditydivergence renormalization, softrapidity correspondence, zetaprescription, and comparison with the experimental measurements.  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Rupert Huber, Institut für Physik, Universität Regensburg  
Nanoelectronics faster than a cycle of light  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Verena Spatz, TU Darmstadt  
Physics Education It is a widely held view that in the field of physics education the implementation of scientific findings into instruction practice should be a critical issue, however the record of research results on genuine classroom activities is generally poor. In the seminar, a project will be presented, that aims at closing this researchpractice gap. In the project, novel teaching units on the introduction to Newtonian mechanics were developed and evaluated, based on empirical studies concerning common preinstruction ideas, which students bring along into school.
Some of these ideas are appropriate, whereas many are inappropriate to build upon in physics lessons. A very popular erroneous idea about motion is that a force is needed to keep an object moving at constant velocity. This novices concept has to be changed into an experts concept, that a force is needed only to change the velocity of an object. As illustrated in this example, teaching and learning physics often requires conceptual change. Considering this, the content area itself had to be restructured and teaching materials had to be prepared to meet students learning needs. An accompanying quasiexperimental field study with grade seven classes showed a significant improvement of students conceptual understanding.  

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Prof. Dr. Stephen D. Hogan, Department of Physics and Astronomy, University College London, UK  
Rydberg states, the bound quantum states of an attractive 1/r potential, play a central role in many precision spectroscopic tests of fundamental physics with atoms and molecules, e.g., [1,2]. As perhaps the simplest Rydberg system, the positronium atom  composed of an electron bound to its antiparticle the positron, and therefore a purely leptonic system described almost entirely by bound state QED theory  offers unique opportunities for studies of this kind. However, because of its short groundstate annihilation lifetime (142 ns) many precision experiments with positronium must be performed with longerlived excited states  Rydberg states. The efficient preparation of Rydberg states in positronium is now possible following developments in positron beam and trap technologies [3], and the motion of the atoms excited to these states can be controlled and manipulated using inhomogeneous electric fields through the methods of RydbergStark deceleration [4]. In this talk I will describe new precision microwave spectroscopic measurements of the triplet n=2 fine structure in positronium that takes advantage of these developments. I will also present a new technique for performing matterwave interferometry with atoms in Rydberg states that has been developed using helium atoms [5], but in the future could be exploited for accurate gravity measurements with Rydberg positronium.
[1] A. Beyer, L. Maisenbacher, A. Matveev, R. Pohl, K. Khabarova, A. Grinin, T. Lamour, D. C. Yost, Th. W. Hänsch, N. Kolachevsky, and Th. Udem, The Rydberg constant and proton size from atomic hydrogen, Science 358, 79 (2017) [2] N. Hölsch, M. Beyer, E. J. Salumbides, K. S. E. Eikema, W. Ubachs, Ch. Jungen, and F. Merkt, Benchmarking Theory with an Improved Measurement of the Ionization and Dissociation Energies of H2, Phys. Rev. Lett. 122, 103002 (2019) [3] T. E. Wall, A. M. Alonso, B. S. Cooper, A. Deller, S. D. Hogan, and D. B. Cassidy, Selective Production of RydbergStark States of Positronium, Phys. Rev. Lett. 114, 173001 (2015) [4] S. D. Hogan, RydbergStark deceleration of atoms and molecules, EPJ Techniques and Instrumentation 3, 1 (2016) [5] J. E. Palmer and S. D. Hogan, Electric Rydbergatom interferometry, Phys. Rev. Lett. 122, 250404 (2019)
 

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Laura Moschini, Brüssel  
Dissociation of exotic nuclei at high energy  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Sascha Rau, MaxPlanckInstitut für Kernphysik, Heidelberg  
Highprecision measurement of the deuterons atomic mass  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Special Colloquium in Memory of Professor Ernst Otten, Mainz  
<i>Prof. Dr. Michèle Leduc, Laboratoire KastlerBrossel, Ecole Normale Supérieure, Paris</i>
<b>"Optical pumping of Helium3 and MRI lung imaging"</b> <p> <p>
<i>Prof. Dr. Wilfried Nörtershäuser, Technische Universität Darmstadt</i>
<b>"Atomic spectroscopy and nuclear structure"</b> <p> <p>
<i>Prof. Dr. Christian Weinheimer, Universität Münster</i>
<b>"The search for the neutrino mass"</b> <p> <p>
<i>Prof. Dr. Werner Heil, Universität Mainz</i>
<b> "Ernst Otten’s Persönlichkeit  Prägung und Wirken der WA EXAKT unter seiner Leitung" </b>
<p>  
Please notice different time and location: Staudinger Lecture Hall/Foyer, MaxPlanck Institute for Polymer Research, Ackermann Weg 10, Tea from 3.00pm 
TheoriePalaver
Institut für Physik 14:30 Uhr s.t., MITP seminar room 
Enrico Morgante, Johannes GutenbergUniversität  
The relaxion mechanism is a proposed solution to the hierarchy problem, in which the EW scale is set by the classical evolution of a scalar field in the early universe. In this talk, I will review this construction and discuss some recent developments.  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Karin Schönning, Upsala University  
Many challenges in modern physics manifest themselves in the proton. Despite being known for a century, it is to this day difficult to describe properties like its mass, spin, structure, size and abundance from first principles. One strategy when you have a system you don’t fully understand, is to make a small change to the system and see how it reacts. In the case of the proton, we can replace one of the light quarks with a heavier one and thereby obtain a hyperon. Hyperons have the advantage over protons and neutrons that their spin is traceable through their weak, parity violating and thereby selfanalysing decay. In this talk, I will outline how various aspects of hyperons can shed light on two of the puzzles related to the proton: the structure and the abundance. In particular, I will discuss how two recent measurement by the BESIII collaboration exploit the unique properties of hyperons and pave the way for a new generation of hyperon physics experiments.
 

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., Newtonraum, 01122, Staudingerweg 9 
Fabian Berressem, Institut für Physik  
BoltzmaNN: Deriving equations of state and effective pair potentials using neural networks  

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Dr. Stephan Schlamminger, National Institute of Standards and Technology, Gaithersburg, USA  
Up to May 20th this year, there was one mass on earth that we knew with absolute precision, i.e., zero uncertainty. This mass was the international prototype of the kilogram. Since May 20th, it is just another mass and thew mass unit is now defined via a fixed value of the Planck constant, h=6.62607015×〖10〗^(34) "J s" with zero uncertainty. In this presentation, I will explain how the unit of mass can be realized at the kilogram scale via the Kibble balance and the Xray crystal density method. In the present SI, it is, however, no longer necessary to realize the unit at the cardinal point of 1 kg, it can be realized at any scale. The talk will present some future possibilities of this scale invariant definition of the mass unit.  
Sondertermin  Bitte um Beachtung! 
Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Hans Christian Lange, Mainz  
We construct a chiral effective Lagrangian for e.m. transitions between vector and pseudoscalar mesons (PVgamma).
Based on an organization scheme in 1/Nc and the quark masses, we fit up to 12 decays and compare the results of our model with the experimental values given in PDG2018.
We will extend our framework to the Dalitz decays PVl+l and compare the calculated decay rates and transition form factors with recent experimental results.  

Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
Johannes Damp, Institut für Physik  
The Level1 Topological Processor at ATLAS: Trigger Performance and Future Upgrades  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Warren S. Warren, Department of Physics, Duke University  
Applying new Physics Insights to improve Tissue Imaging  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Alejandro Kievsky, INFN Pisa  
The shortrange interaction between particles many times shows a strong repulsion that strongly correlated the manybody system. In the particular case of a twobody shallow state, very extended compared to the range of the interaction, the threebody system has universal behavior.
There is an infinite number of states geometrically accumulated at E=0.
This is the Efimov effect predicted by V. Efimov in 1970 and experimentally verified more than 25 years later. I will discuss how universal behavior emerges in strongly correlated systems as liquid drops or light nuclear systems and how this behavior propagates as the number of particle increases.
 

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Dr. Johannes W. Deiglmayr, FelixBloch Institute, Universität Leipzig  
Exciting an atom or molecule into a highlying electronic state, a Rydberg state, changes its properties in a drastic, but very wellunderstood way. While the binding energy of the Rydberg electron decrease with the principal quantum number n as 1/n^2, the orbital radius and transition dipole moments increase as n^2. This results in the electric polarizability increasing as n^7. I will present recent experiments in which we have exploited these scaling laws and exaggerated properties to perform precision measurements of ionization energies with relative accuracies up to 10^11, to characterize precisely static and alternating electric fields, and to reduce the detrimental role of stray fields in applications of Rydberg atoms. In a second part, I’ll discuss our progress towards extracting accurate scattering phase shifts from the spectroscopy of heteronuclear longrange Rydberg molecules, which are bound by the interaction of the Rydberg electron with groundstate atoms within its orbit, and how we plan to exploit the exotic properties of longrange Rydberg molecules to create ultracold, strongly correlated plasmas.  

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Asia Sobczyk, Valencia  
Nuclear effects for neutrino oscillation studies  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Dr. Simon Sels, CERN  
Recent developments for laser spectroscopy of shortlived isotopes at radioactive ion beam facilities  

Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
Peter Berta, Institut für Physik  
Pileup mitigation for jets with Iterative Constituent Subtraction  

TheoriePalaver
Institut für Physik 14:30 Uhr s.t., MITP seminar room 
Leonardo Vernazza, Nikhef  
Scattering processes near threshold develop large logarithms, that need to be resummed. In my talk I will focus in particular on electroweak annihilation processes, such as DrellYan and Higgs production in gluon fusion, and discuss the underlying factorisation theorems which allow the resummation of such logarithms at nexttoleading power, comparing diagrammatic and effective field theory methods.  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Werner Krauth, Laboratoire de Physique, cole normale suprieure, CNRS Paris  
Fast irreversible Markov chains in statistical physics  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Christian Weinheimer, Universität Münster  
Since the discovery of neutrino oscillation we know that neutrinos have nonzero masses, but we do not know the absolute neutrino mass scale, which is as important for cosmology as for particle physics. The direct search for a nonzero neutrino mass from endpoint spectra of weak decays is complementary to the search for neutrinoless double betadecay and analyses of cosmological data.
Today the most stringent direct limits on the neutrino mass originate from investigations of the electron energy spectra of tritium betadecay.
The next generation experiment KATRIN, the Karlsruhe Tritium Neutrino experiment, is improving the sensitivity from the tritium beta decay experiments at Mainz and Troitsk of 2 eV/c^2 by one order of magnitude probing the region relevant for structure formation in the universe. KATRIN uses a strong windowless gaseous molecular tritium source combined with a huge MACEFilter as electron spectrometer. To achieve the sensitivity, KATRIN has been putting many technologies at their limits. The full 70m long setup has been successfully commissioned. From early 2019 on KATRIN is taking high statistics tritium data hunting for the neutrino mass.
In this talk an introduction into the necessity to determine the neutrino mass and the status in the field will be given, followed by a detailed presentation of KATRIN and its results from the first KATRIN science run. The new results are already bringing KATRIN into the lead position of the field. In the outlook the perspectives of KATRIN for the coming years and new technologies in the field to potentially improve further the sensitivity on the neutrino mass will be presented.
 

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., Newtonraum, 01122, Staudingerweg 9 
Dr. Anbumozhi Angayarkan Somasundaram, Weizmann Institute, Rehovot, Israel  
Phosphatidylcholine (PC) lipids complexed with hyaluronan (HA) have been proposed to form strongly lubricating boundary layers at biosurfaces such as articular cartilage. Depending on the type of PC used, efficient lubrication with friction coefficients down to 104 under physiologically high pressures (~100 atm) have been observed. This was attributed to hydration lubrication, acting at the highly hydrated phosphocholine headgroups of the PC lipids, exposed at the liposome surfaces. Such hydration layers can sustain large compressions without water molecules being squeezed out from the gap between sliding surfaces. At the same time, the hydration shells can relax rapidly, ensuring a fluid like response under applied shear. This combination of low shear stresses while sliding under high normal stresses results in very low friction coefficients, an effect termed hydration lubrication. We use the surface force balance (SFB) to examine interactions between polymer layers, in particular how normal interactions and especially frictional interactions, are modified when PC liposomes are added surface in pure water and in aqueous salt solutions, mimicking the presence of macromolecules on the surface of cartilage.  

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Farah Afzal, Bonn  
Baryon spectroscopy via measurement of polarization observables  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Dr. Sebastian Raeder, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt  
Shedding light on heavy actinides  laser spectroscopic investigations of Es and Fm isotopes in Mainz  

Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
John RackHelleis, Institut für Physik  
Efficiency determination of the wavelengthshifting optical module  
Masterkolloqium 
Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Torsten Enßlin, Max Planck Institute for Astrophysics, Garching  
Information Field Theory: Turning Data into Images  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Javier Menéndez, Universitad de Barcelona  
The rare decay of atomic nuclei known as neutrinoless doublebeta Decay is a unique process. Here, a nucleus decays by turning two neutrons into two protons, emitting two electrons without the usual balance of antineutrinos. Therefore, two particlestwo electronsare effectively created. Neutrinoless doublebeta decay is the most promising attempt to test lepton number conservation in the laboratory.
The observation of neutrinoless doublebeta decay would proof that neutrinos are its own antiparticle, can clarify the origin of the prevalence of matter over antimatter in the universe, and determine the absolute neutrino mass. In spite of formidable experimental efforts, neutrinoless doublebeta decay remains elusive, with halflive limits set over 10^25 years in some nuclei.
The decay rate depends critically on the nuclear structure of the initial and final nuclei. This is encoded in the nuclear matrix element, which is key to anticipate the reach of experiments and to fully extract all physics information from a future measurement. In this PRISMA+ colloquium I will summarize the status of doublebeta decay searches, and highlight recent efforts to obtain reliable nuclear matrix elements from first principles.
 

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Dr. Juan Manuel CornejoGarcia, Institut für Quantenoptik, Universität Hannover  
Cosmological observations point to an apparent imbalance of matter and antimatter in our universe, which contrasts with the nearly perfect symmetry arising on the level of single particles. Tests for hypothetical limits to this symmetry rest on high precision comparisons of the fundamental properties of particles and antiparticles  for example, with measurements of the proton and antiproton gfactors in Penning traps. However, these measurements rely on cooling and detections schemes that are highly sensitive on the particle's motional energy [1,2].
In this talk, it will be shown an alternative experimental method which enables a speed up of the particles' preparation and a boost in readout fidelity in the respective experiments [3]. Our method allows for sympathetic cooling of a proton or antiproton to its quantum mechanical ground state and provides readout of their spin state, by means of coupling to a laser cooled 9Be+ ion cotrapped in a double well potential. In addition, an overview of the current experimental setup featuring a cryogenic Penning trap stack for first demonstrations of motional coupling between two 9Be+ ions will be presented.
[1] C. Smorra et al., Nature 550, 371374 (2017) [2] G. Schneider et al., Science 358, 10811084 (2017) [3] D. J. Wineland et al., J. Res. NIST 103, 259328 (1998)
 

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Vadim Lensky, Mainz  
Nuclear structure contribution to the Lamb shift of muonic deuterium in pionless effective field theory  

Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
Florian Thomas, Institut für Physik  
Ultrafast raytracing for the WavelengthShifting Optical Module  
Masterkolloqium 
Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Daniel Glückman, Karlsruher Institut für Technologie, Institut für Nukleare Entsorgung  
Ultratrace determination of actinides in clay systems with accelerator mass spectrometry and development of a diffusion setup for reducing conditions  

TheoriePalaver
Institut für Physik 14:30 Uhr s.t., MITP seminar room 
Matthias Heller, Johannes GutenbergUniversität  
The DrellYan production of charged lepton pairs is one of the key processes measured at hadron colliders. The QCD corrections to the crosssection are known to order \(\alpha_s^2\) and electroweak corrections are known to order \(\alpha\). The next important step for a better theoretical understanding is the complete calculation of the mixed QCDEW corrections of order \(\alpha \alpha_s\). In this talk, I report on the first calculation of the virtual twoloop corrections of order \(\alpha \alpha_s\) to the crosssection. The calculation is carried out analytically using tensor reduction, IBP relations and the method of differential equations. We validate a previous calculation of the subset of mixed QCDQED corrections and show how the jet and soft functions of that reference can be used to subtract the infrared divergencies of the complete mixed QCDelectroweak virtual corrections. In the talk, I will focus on the calculation of the master integrals, which involve algebraic letters in the differential equation.  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Hendrik Hildebrandt, Faculty of Physics and Astronomy, RU Bochum  
Observational cosmology with redshift galaxy  

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., Newtonraum, 01122, Staudingerweg 9 
Dr. Jianxiang Shen, Institut für Physik  
Structure and properties of polymer nanocomposites from molecular dynamics simulations  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik Sonderseminar: 10:00 Uhr s.t., MEDIENRaum, Staudinger Weg 7, 3. Stock, 03431 
Akashdeep Ghalayan, Indian Institute of Technology Delhi, India  
Heusler Alloys have been widely studied due to their potential applications in spintronic devices. Understanding the material's magnetic properties is crucial for deciding its devicebased applications. Heusler alloys with high spin polarization (~100 %) and high Curie temperature (~1000 K) are one of the most preferred materials in this regard. The cobaltbased Co2MnAl (CMA) Heusler alloys exhibit more than 50% spin polarization even in the disordered phase with high Curie temperature (Tc ~ 697 K) which is beneficial for device applications. Thin films of CMA with different CoMn concentrations have been grown using DC magnetron sputtering at constant growth temperature (Ts ~ 400°C) and film thickness (~ 50 nm) to investigate the effect of Co/Mn concentrations on their electrical transport behavior. Xray diffraction studies revealed that films possess the A2 disordered phase at room temperature. Magnetic anisotropy, which is vital for magnetic switching device applications, has been investigated using the Longitudinal MagnetoOptic Kerr Effect technique. LMOKE studies revealed the presence of uniaxial magnetic anisotropy in these films. The origin of the uniaxial anisotropy in our films is attributed to obliquely directed material flux onto the substrates during the filmgrowth.  
Sonderseminar  

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Ethan Cline, MIT  
In 2010 when the CREMA Collaboration released their measurement of the proton radius (Pohl et. al (2010)) from muonic hydrogen spectroscopy: rp=0.84184(67) fm. This was seven standard deviations smaller than the accepted 2010 CODATA value (0.8768(69) fm). This discrepancy lies at the heart of the proton radius puzzle. The MUonProton Scattering Experiment (MUSE) was first proposed in 2012 to be the first muonproton elastic scattering experiment with sufficient precision to address the proton radius puzzle. MUSE has the capacity to simultaneously measure elastic muonproton, and electronproton scattering, and switch polarities to measure with opposite charge states. As such, MUSE can directly measure the twophoton effect by comparing chargestates, and compare muon and electron scattering with minimal systematic error. By comparing the two measured scattering cross sections, the experiment will provide more data for the proton radius puzzle and determine if the radius is the same in electron and muonproton scattering. We will review the motivation for and status of MUSE, which is due to begin production running in 2020. Initial analysis results will be shown from the summer 2019 beam time.  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Katerina Chrysalidis, Universität Mainz / CERN  
Improving the spectral coverage and selectivity of the ISOLDE RILIS  

Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
Kai Loo, Institut für Physik  
Online Scintillator Internal Radioactivity Investigation System (OSIRIS) for JUNO  

TheoriePalaver
Institut für Physik 14:30 Uhr s.t., MITP seminar room 
Guoxing Wang, Peking University  
The invariant mass distribution of top quark pair production is an important observable whose threshold behavior is sensitive to topquark mass. In this talk, I will focus on the invariant mass distribution of topquark pair production in threshold region and soft region. I will first talk about the resummation of Coulomb corrections in threshold limit β → 0. We combine the resummation with fixedorder results and present phenomenologically relevant numeric results. We find that the resummation effect significantly enhances the differential cross section in the threshold region, and makes the theoretical prediction more compatible with experimental data. As for soft limit z → 1, I’ll talk about the calculation of NNLO soft function which is a major bottleneck in pushing up the soft resummation accuracy of topquark pair production. We show the nontrivial structure of threeparton correlations and the consistent extraction of NNLO soft fragmentation function. At the end, I’ll show the preliminary results of hard function and its application to transverse momentum resummation for topquark pair production and decay in the future.  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Laura Fabbietti, Physics Department, TU Munich  
A new Laboratory to study HadronHadron Interactions  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik 12:00 Uhr s.t., NewtonRaum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) 
Alexander Tries, Inst. f. Physik  
tba  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Torben Ferber, DESY Hamburg  
Belle II in Japan is a flagship experiment at the intensity frontier that started data taking this year after massive upgrades of the accelerator and the detector.
In this talk I will report on the performance of the Belle II detector and first rediscoveries with the 2019 dataset.
In the second part of the talk I will give an overview about the planned Belle II physics program for the next year with a focus on searches for Dark Sectors and LongLived Particles.  

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Dr. Guillaume Salomon, MaxPlanckInstitut für Quantenoptik, Garching  
Developing new approaches to study quantum manybody systems is of fundamental importance in various felds of physics ranging from high energy and condensed matter physics to quantum information and quantum computation. It also holds promise for a better understanding of materials, such as highTc superconductors, and faulttolerant quantum computing which could strongly impact our modern societies. Ultracold atoms have emerged as versatile and well controlled platforms to study fundamental problems in quantum manybody physics. In particular, spinresolved quantum gas microscopy enables to probe strongly correlated fermions with a resolution down to the single particle and offers fascinating opportunities for experiments. I will detail here this technique and discuss our recent experimental studies of the interplay between magnetism and doping in the FermiHubbard model, a minimal model for highTc superconductivity.
 

SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 13:30 Uhr s.t., MAINZSeminarraum, Staudinger Weg 9, 03122 
Camilo Ulloa, Utrecht University, NL  
In this talk I will discuss the main concepts of magnon transport through magnetic insulators. I will focus my talk on how to excite and manipulate magnetic degrees of freedom in ferromagnetic materials, and show some of the different ways we can model magnetic insulators, going from quantum mechanics to hydrodynamics.  

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Varvara Batozskaya, National Centre for Nuclear Research, Warsaw  
The measurement of the mixinginduced CPviolating phase phi_s in the Bs − B̄s system is one of the key goals of the LHCb experiment. It has been measured at the LHCb collaboration with several decay channels. Thanks to the precise prediction of the phi_s value in the frame of the Standard Model, it represents an excellent probe to search for new physics.  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Dr. Christoph Solbach, Universitätsklinikum Ulm  
Zur Produktion von Zr89 an einem PETtraceZyklotron  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Jos Lelieveld, Max Planck Institute for Chemistry, Mainz  
Impacts of anthropogenic emissions on public health, rainfall and climate  

TheoriePalaver
Institut für Physik 14:30 Uhr s.t., MITP seminar room 
Fazlollah Hajkarim, Frankfurt University  
Using the quantum chromodynamics (QCD) equation of state (EoS) from lattice calculations we investigated QCD effects on the first order primordial gravitational waves (PGWs) produced during the inflationary era. We also considered the cases for vanishing and nonvanishing lepton asymmetry where the latter one is constrained by cosmic microwave background experiments. Also, we investigated scenarios that inflation is succeeded by a phase where the energy density of the Universe was dominated by a scalar component with a general equation of state. Then we evaluated the spectrum of primordial gravitational waves induced in the postinflationary Universe. We showed that if the energy density of the Universe was dominated by some specific fluid 𝜙 before Big Bang Nucleosynthesis (BBN), its equation of state could be constrained by gravitational wave experiments. Moreover, we studied the effect of QCD and electroweak transitions on the induced (or second order) PGW from scalar perturbations which is different from the first order PGW spectrum. Finally, I briefly discuss the production of dark matter (DM) in an early matter era dominated by a heavy long lived scalar field.  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik 12:00 Uhr s.t., NewtonRaum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) 
Mariia Filianina, Inst. f. Physik  
Electric fieldinduced strain control of magnetism in inplane and outofplane magnetized thin films  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Felix Kahlhoefer, RWTH Aachen  
Over many years the experimental programme to search for dark matter has been guided by the socalled freezeout paradigm, which assumes that interactions between the dark matter and Standard Model particles are comparable in strength to weak interactions. The nonobservation of any dark matter signal has challenged this idea and led to a shift of focus towards dark matter models with even weaker interactions. At first sight, the chance of discovering such particles appears very low, but there are a number of exciting cases where potentially observable signals are predicted in spite of tiny couplings. I will present cosmological and phenomenological aspects of these models and discuss how existing and planned experiments can be used to search for such hidden particles.
 

SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers Sonderseminar: 10:00 Uhr s.t., GernotGraeffRaum, Staudinger Weg 7, 05431 
Joel Moore, University of California, Berkeley, and Lawrence Berkeley National Laboratory  
This talk starts by reviewing known examples of how topological materials generate new kinds of electrodynamic couplings and effects. Threedimensional topological insulators realize a particular electromagnetic coupling known as “axion electrodynamics”, and understanding this leads to an improved understanding of magnetoelectricity in all materials. We then turn to how topological Weyl and Dirac semimetals can show unique electromagnetic responses; we argue that in linear response the main observable effect solves an old problem via the orbital moment of Bloch electrons, and how in nonlinear optics there should be a new quantized effect, which may have been seen experimentally. This nonlinear effect has a natural quantum e^3/h^2 and appears in chiral Weyl semimetals over a finite range of frequencies. We discuss interaction and disorder corrections to nonlinear responses in closing.  
Sonderseminar  
TOPDYN 
Theory of Condensed Matter: Hard Condensed Matter
Institut für Physik, SPICE 10:00 Uhr s.t., Room 05431 (GernotGräffRaum) 
Joel Moore, University of California, Berkeley, and Lawrence Berkeley National Laboratory  
This talk starts by reviewing known examples of how topological materials generate new kinds of electrodynamic couplings and effects. Threedimensional topological insulators realize a particular electromagnetic coupling known as “axion electrodynamics”, and understanding this leads to an improved understanding of magnetoelectricity in all materials. We then turn to how topological Weyl and Dirac semimetals can show unique electromagnetic responses; we argue that in linear response the main observable effect solves an old problem via the orbital moment of Bloch electrons, and how in nonlinear optics there should be a new quantized effect, which may have been seen experimentally. This nonlinear effect has a natural quantum e^3/h^2 and appears in chiral Weyl semimetals over a finite range of frequencies. We discuss interaction and disorder corrections to nonlinear responses in closing.
Work with F. de Juan, A. Grushin, T. Morimoto, D. Parker, J. Orenstein, C. Felser, T. Torchinsky, and others.
 

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Prof. Dr. Sile Nic Chormaic, OIST Graduate University, Okinawa, Japan  
Ultrathin optical fibres, with diameters on the order of the propagating light wavelength, have already proven their versatility across a variety of different areas, such as sensing, particle manipulation, cold atom physics, and as optical couplers. The intense evanescent field at the fibre waist is one of the main advantages offered by these systems as it allows us to achieve ultrahigh light intensities that may otherwise not be attainable in a standard laboratory. In this talk, I will present work conducted at OIST with particular focus on our work on optical nanofibremediated multiphoton processes for the generation of highly excited Rydberg atoms and for exploring some other effects, such as quadrupole transitions and stimulated emission from Rb atoms. Overall, the versatility of these fibres for many different experimental platforms particularly if one goes beyond the basic, single mode fibre design will be promoted.  

SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 13:30 Uhr s.t., MAINZSeminarraum, Staudinger Weg 9, 03122 
Prof. Dennis Meier, Norwegian University of Science and Technology, Trondheim  
Domain walls naturally arise whenever a symmetry is spontaneously broken. They interconnect regions with different realizations of the broken symmetry, promoting structure formation from cosmological length scales to the atomic level. In my talk, I will present domain walls with unique functionalities which emerge in spinspiral multiferroics and chiral magnets and which hold great promise for nanoelectronics and spintronics applications. In particular, I will discuss that a wide variety of new domain walls occurs in the presence of spatially modulated domain states. In contrast to domain walls in conventional ferroics, such domain walls exhibit a welldefined inner structure, which — analogous to cholesteric liquid crystals — consists of topological disclination and dislocation defects. Similar to the magnetic skyrmions, the domain walls can carry a finite topological charge, permitting an efficient coupling to spin currents and contributions to a topological Hall effect. Our studies establish domain walls in chiral magnets as functional nanoobjects with nontrivial topology, opening the door to innovative device concepts in information and communication nanotechnology.  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Dr. Nadine Chiera, PSI, Schweiz  
Chemical investigation of exotic radionuclides  

Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
Niklas Schmitt, University of Mainz  
Suche nach dunkler Energie in MonojetEreignissen bei 13TeV mithilfe des ATLASDetektors am LHC  
Bachelorkolloqium 
Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Christian Enss , Kirchhoff Institute for Physics, Heidelberg  
Small, Cold and Universal: Cryogenic MicroCalorimeters a New Key Technology  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Cristina Lazzeroni, University Birmingham, UK  
The decay K+→π+vv ̅, with a very precisely predicted branching ratio of less than 1010, is one of the best candidates to reveal indirect effects of new physics at the highest mass scales. The NA62 experiment at the CERN SPS is designed to measure the branching ratio of the K+→π+vv ̅ with a decayinflight technique. NA62 took data so far in 20162018. Statistics collected in 2016 allowed NA62 to reach the Standard Model sensitivity for K+→π+vv ̅, entering the domain of 1010 single event sensitivity and showing the proof of principle of the experiment. Thanks to the statistics collected in 2017, NA62 surpasses the present best sensitivity. The preliminary result from the 2017 data set is presented. The general status of the experiment, including other recent measurements, are presented. Plans for the next data taking and for a longer term future are also discussed.
 

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Jun.Prof. Dr. Jamir Marino, Institut für Physik, Universität Mainz  
The talk will discuss instances of dynamical phases of interacting quantum many body models where coherent and dissipative dynamics occur on equal footing, shaping novel nonequilibrium phase diagrams. The first part of the talk will discuss longrange interacting quantum simulators where an external periodically driven field can stabilise phases without equilibrium counterpart against instabilities triggered by many body quantum fluctuations. In the second part, I will present an instance of ‘cold' time crystal occurring in open quantum systems, where neither MBL or prethermalisation are required to stabilise a strongly interacting nonequilibrium steady state. Time permitting, I will advertise some novel results on a purely dissipative analogue of longrange interacting quantum simulators, which can be implemented in quantum optics or solid state platforms.  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Dr. Marine Vandebrouck, CEA Saclay  
243Es, 249Md: from production crosssections measurement to spectroscopy  Perspectives at GANILSPIRAL2/S3  

Theoriekolloquium
Die Dozierenden der Theoretischen Physik Sonderseminar: 14:00 Uhr s.t., Medienraum, Staudinger Weg 7, 03431 
Prof. James Freericks, Georgetown University, USA  
Quantum mechanics was created with the matrix mechanics of Heisenberg, Born, and Jordan. Schroedingers wave mechanics shortly followed and allowed for simpler and more powerful calculations. Both Pauli and Dirac introduced a formulation of quantum mechanics based on operators and commutation relations, but it was never fully developed in the 1920s. Instead, Schroedinger formulated the operator approach with his factorization method, which later was adopted by the highenergy community as supersymmetric quantum mechanics. In this talk, I will explain how one can formulate all of quantum mechanics algebraically by a proper use of the translation operator on top of Schroedingers factorization method. I will give examples of how one can compute spherical harmonics algebraically, how one can find harmonic oscillator wavefunctions, and will even describe an operatorbased derivation of the wavefunctions of Hydrogen. I will end with a proposal for a novel way to teach quantum mechanics, focusing first on conceptual ideas related to superposition, projective measurements, and entanglement. Then developing more conventional topics like spin, harmonic oscillator, angular momentum, interacting spin models, central potentials, particles in a box and so on. This is the subject of a book in progress entitled Quantum Mechanics without Calculus.  
Sonderseminar  
Sondertermin/raum Montag, 14:15 h im Medienraum, Staudinger Weg 7, 03431 
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
Julian Fischer, Institut für Physik  
Development of an EM trigger algorithm in the ATLAS forward region  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik Sonderseminar: 10:00 Uhr s.t., MEDIENRaum, Staudingerweg 7, 3. Stock, Raum 03431 
Abhishek Erram , Indian Institute of Technology Kharagpur  
In this work, we have made a polycrystalline sample of Dy2BaNiO5 by a standard solidstate reaction route. The formation of the compound was ascertained by xray powder diffraction pattern. The dc χ measurements were carried out in the temperature interval 5–300 K in the presence of magnetic fields of 100 Oe and 5 kOe for zerofieldcooled (zfc) and fieldcooled (fc) conditions using (SQUID) and isothermal magnetization (M) behavior was studied at a certain selected low temperature. Then, Thin film of Dy2BaNiO5 certain thickness were deposited on Mgo , Al203 ,STO and LAO substrate by Pulsed Layer Deposition method these films were annealed at temperature 650 oC. Some of the samples were Characterized by Xray diffraction (XRD). Magnetic behavior was also studied. Results show that of formation of thin film. Signs of magnetic behavior was also evident.  
Sonderseminar  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Christian Fischer, Universität Gießen  
In this talk I will give an overview on recent results on the spectrum and properties of conventional baryons and 'exotic' tetraquarks as obtained in the framework of DysonSchwinger and BetheSalpeter equations. I will discuss the spectrum of light baryons with focus on the comparison with quark model expectations, the impact of dynamical mass generation and the importance of relativistic components in the wave functions of baryons. I will also discuss extensions to SU(3).
For fourquark systems I will summarize results for light quarks and discuss recent progress on discriminating between tetraquark, molecule or hadroquarkonium configurations in heavylight systems.
 

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 10:30 Uhr s.t., QUANTUM Seminarraum (02427), Institut für Physik, Staudingerweg 7 
Brian Rost and Lorenzo Del Re , Georgetown, USA  
The driven dissipative many body problem is one of the longest standing unsolved problems in physics and it has experienced a renewed interest in the last decade. In fact, dissipation has been theoretically proposed as a resource for quantum computation and experimentally has been demonstrated that it can be employed to prepare maximally entangled states.
Thus, quantum computers could shed some light on the unsolved problem of drivendissipative quantum systems but there are many choices for how one engineers the reservoir. An attractive approach is to integrate the bath degrees of freedom out via a master equation. Here we show how accurate this approach is by comparing it to an exact solution in the case of a tightbinding dissipativedriven model of fermions coupled to an external fermionic bath, and how to actually simulate it on a currently available IBM quantum computer. We also address the case of an interacting dissipativedriven finite size system, i.e. a threesite Hubbard model with onsite interaction driven by an external field and coupled to a bath. Here, we obtain many of the qualitative features already displayed in the thermodynamic limit. The biggest challenge in implementing these ideas on current quantum computers lies with the need for partial resetting of qubits. We discuss strategies to implement on commercially available hardware and what might be possible with academic machines (such as those available at Mainz).
 
Sondertermin und ort 
SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 11:30 Uhr s.t., MAINZSeminarraum, Staudinger Weg 9, 03122 
Dr. Dongwook Go, Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich  
Electrical control of magnetism is a central theme in the field of spinorbitronics. Current scheme relies on electrical generation of the spin current/density by utilizing the spinorbit coupling (SOC) instead of using an extra ferromagnet (FM) as a spin polarizer. For example, in a bilayer structure consisting of a FM layer and a nonmagnet (NM) layer, spin current and density can be induced by the spin Hall effect in the NM and RashbaEdelstein effect at the NM/FM interface, respectively. However, there has been a missing piece in spinorbitronics so far: electrons carry angular momentum in the orbital wave function as well as in the spin. In this seminar, I demonstrate that the orbital degree of freedom exhibits rich dynamical phenomena, which is in contrast to a common expectation that the orbital is quenched in solids.
In the first part, I explain how to electrically generate the orbital angular momentum. Here, I introduce concepts of the orbital RashbaEdelstein effect [1] and the orbital Hall effect [2], which are orbital analogs of the Rashba effect and the spin Hall effect, respectively. These are not only parental effects for their spin analogs, such that the spin phenomena follow the orbital phenomena by the SOC, but also present even in the absence of the SOC. In the second part, I focus on the consequence of the injection of the orbital angular momentum into the FM. As the spin injection gives rise to the spin torque (ST), the orbital injection results in torque on the magnetic moment, which we call orbital torque (OT) [3]. In the mechanism of the OT, it is not necessary to prepare the spin current or density beforehand as in the conventional mechanisms such as the spin Hall effect and RashbaEdelstein effect. Since both OT and ST contribute to magnetic dynamics, it opens a route to enhancing the torque efficiency in spinorbitronic devices. Interestingly, we notice that the sign of the torque efficiency in the NM/FM bilayer can be opposite to the sign of the spin Hall effect in the NM if the sign of the OT differs from that of the ST. As a prototypical example, I compare Fe/W(110) and Ni/W(110) bilayers from first principles calculation and discuss qualitatively distinct features of the OT for the experimental detection [4]. As the study on the orbital dynamics has started very recently, I briefly discuss future directions for consistent understanding of entangled dynamics of the spin and orbital degrees of freedom in solids.
 

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Shane P. Kelly, Theoretical Division, LANL, Los Alamos, USA  
In recent years, many experimental platforms have succeeded in producing quantumsystems that, on relevant time scales, are completely isolated from an environment.
This opens the possibility of observing equilibrium states that are not described by standard thermal ensembles and long time dynamics that indefinitely maintain memory of initial states.
In this talk, I discuss two mechanisms for this to occur: many body localization (MBL) and a novel mechanism which occurs in the semiclassical limit of a large spin.
In the first part of my talk, I will discuss the phenomenon of MBL in a disordered spin chain and its effects when coupled to a small environment.
We model this small environment as a clean spin chain and find that, under sufficient coupling and disorder, the dirty chain can induce an MBL effect in the clean chain.
In the second part of my talk, I will discuss the dynamics of a large spin evolving with a nonlinear hamiltonian.
Using semiclassical techniques, we identify when the spin does and does not thermalize.
In doing so, we find a novel mechanism for the breakdown of thermalization based on the slow dynamics of an unstable fixed point.
 

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Christoph Matejcek, Mainz  
Lowenergy beam transport system for MESA  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Dr. Zsolt Baranyi, Universität BRACCO  
Thema folgt  

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 16:15 Uhr s.t., QUANTUM Seminarraum (02427), Institut für Physik, Staudingerweg 7 
Dr. Guanghua Du, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China  
When heavy ion beam with energy from MeV to GeV is incident on the target material, the target material distributed along the ion trajectory will be excited or ionized, which will cause lattice damage, polymer chain break or crosslinking in the material and then result in nanoscale latent track, cluster damage and single event effect. The high energy microbeam facility of Lanzhou National Laboratory of Heavy Ion Accelerator is the highest energy microbeam system in the world which uses tripletquadrupole magnets to produce micron sized high energy ion beams of up to several GeVs. This talk first introduces the accelerator complex and nuclear physics activity at Lanzhou National Lab, and then focuses on the interdisciplinary application of the high energy microbeam facility, including single event effect studies, single ion hitting, nanomaterials, and biomedical studies.  
Sondertermin und ort 
Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Victorino Franco, Condensed Matter Physics, Universidad de Sevilla  
Phase Transitions and Critical Phenomena  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik 12:00 Uhr s.t., NewtonRaum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) 
Olga Lozhkina, Inst. f. Physik  
tba  

Theory of Condensed Matter: Hard Condensed Matter
Institut für Physik, SPICE 14:00 Uhr s.t., Galilei Room, 01128 (Staudinger Weg 9) 
Souvik Paul, ChristianAlbrechtsUniversität zu Kiel  
Magnetic skyrmions, localized spin structure with topological protection, have become a research hotspot as they show promise for future memory and logic devices. The key challenges for applications are to achieve small bits and stability of those skyrmionic bits. Research shows that transitionmetal interfaces (TMI) and multilayers are a very promising class of systems to realize nanometersized and stable magnetic skyrmions. Therefore, a lot of effort has been put to tailor the properties of these systems for application.
In this direction, using firstprinciples methods, we have proposed ultrathin films, Fe/Rh and Rh/Fe bilayers on Re(0001) substrate, which show various spin structures at the interface including isolated skyrmions, depending on the stacking order of Fe/Rh and Rh/Fe bilayers. This study would encourage the experimentalist to check our predictions and would generate more investigations on other bilayers on Re(0001).
The other topic I would focus on is the effect of higherorder exchange interactions (HOI) on the stability of skyrmions. HOI are shown to stabilize magnetic ground states in transitionmetal ultrathin films, however, their role on the stability of metastable skyrmions has note been investigated yet. We showed that the HOI increase the stability of skyrmions by a large amount at TMI. This study opens up a route to tune skyrmions stability and lifetime in ultrathin films.
[1] Nat. Nanotechnol. 8, 899–911 (2013)
[2] Sci. Rep. 4, 6784 (2014)
[3] Nat. Commun. 5, 4652 (2014)
[4] arXiv:1912.03465
[5] Nat. Phys. 7, 713 (2011)
[6] Phys. Rev. Lett. 120, 207201 (2018)
[7] Phys. Rev. Lett. 120, 207202 (2018)
[8] arXiv:1912.03474  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Assumpta Parreno, Universitad de Barcelona  
A central goal of Nuclear Physics is to obtain a firstprinciples description of the properties and interactions of nuclei from the underlying theory of the strong interaction, Quantum Chromodynamics (QCD). Being the theory that governs the interactions between the basic building blocks of matter, quarks and gluons, it is also responsible for confining those primary pieces into hadronic states, binding neutrons and protons through the nuclear force to give the different elements in the periodic table. Nevertheless, due to the large complexity of the quarkgluon dynamics, one cannot obtain analytical solutions of QCD in the energy regime relevant to nuclear physics. In order to address this problem, numerical solutions of QCD can be obtained in a finite volume through its formulation in a Euclidean discretized spacetime. I will present the results of our study in the twobaryon sector for different values of the light quark masses, as well as for the very light A=3,4 nuclei.
 

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Dr. Maria Chekhova, Institut für Optik, Information und Photonik, Universität Erlangen  
Spontaneous parametric downconversion is the workhorse of quantum optics. This process is used to generate entangled photon pairs and heralded single photons. When strongly pumped, spontaneous parametric downconversion generates so many photon pairs that they overlap and form radiation with almost laser brightness. Despite being bright, this radiation manifests nonclassical effects: quadrature squeezing, photonnumber correlations, and macroscopic entanglement. It has no coherent component and can be considered as amplified vacuum noise; it is therefore often called bright squeezed vacuum. In addition, strong photonnumber fluctuations of bright squeezed vacuum make it extremely efficient for pumping multiphoton effects.
My talk will cover this and other applications of strongly pumped parametric downconversion. In addition, I will talk about the other extreme case of this process. Namely, if photon pairs are generated in a very thin nonlinear layer, the process does not require phase matching – in other words, the momentum of the pump photon is not conserved by the daughter photons. To demonstrate this, I will show the results of generating photon pairs from a 300 nm layer. This nanoscale generation of entangled photons offers unique radiative characteristics: the frequencyangular spectrum is extremely broad and as such it promises subwavelength and subcycle twophoton correlation widths in position and time, respectively. Additionally, it gives an insight into the subwavelength resonances for vacuum fluctuations.
 

SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 14:00 Uhr s.t., MAINZSeminarraum, Staudinger Weg 9, 03122 
Stéphane Mangin, Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, Nancy, France  
During the last decade alloptical ultrafast magnetization switching in magnetic material thin film without the assistance of an applied external magnetic field has been explored [1,2]. It has been shown that femtosecond light pulses can induce magnetization reversal in a large variety of magnetic materials [3,4]. However, so far, only certain particular ferrimagnetic thin films exhibit magnetization switching via a single femtosecond optical pulse. We will present the singlepulse switching of various magnetic material (ferrimagnetic, ferromagnetic) within a magnetic spinvalve structure and further show that the four possible magnetic configurations of the spin valve can be accessed using a sequence of single femtosecond light pulses. Our experimental study reveals that the magnetization states are determined by spinpolarized currents generated by the light pulse interactions with the GdFeCo layer [5]. A detail study showing how spinpolarized currents are generated and how they interact with magnetic layers (Ferromagnetic or Ferrimagnetic) to lead to magnetization switching will be presented.  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik 13:30 Uhr s.t., MEDIENRaum, Staudingerweg 7, 3. Stock, Raum 03431 
Mona Minakshee Manjaree Bhukta , National Institute of science education and research, Bhubaneswar, India  
1.Thermal diffusion of nπ Skyrmion and Skyrmion bags Skyrmionics have recently emerged as active field of research because of their potential applications in high density data storage technology and logic gate computing. Magnetic skyrmions correspond to localized whirling spin configurations, which are characterized by a topological charger (Q). Recent atomistic simulations and experimental finding ensure the diffusive behaviour of skyrmion at finite temperatures in ultrathin model, which open up the possibility of application thermal induced skyrmion dynamics in probabilistic computing. In this work we studied the thermal diffusion of nπ skyrmion up to n= 5 and N skyrmion bag (N (= 16) skyrmion surrounded by a bigger skyrmion with opposite chirality) using atomistic spin simulation on Pt_{0.95}/Ir_{0.05} on Pd (111) bilayer by statistically averaging out 100s of these spin texture. Further the SkHE of all these structures has been calculated using both simulation and analytics.
2.Frustrated Skyrmionic States in synthetic Antiferromagnet The spherical topology of a skyrmion leads to an extra force, that acts on moving skyrmion, pointing perpendicular to its velocity. This deviates the path of the skyrmion towards the edge of the nanotrack and this phenomenon is referred as the Skyrmion Hall effect (SkHE). In an antiferromagnetically exchangecoupled bilayer nanotrack, this SkHE could be suppressed without affecting the topological protection of the skyrmion. Recently it is shown that skyrmion in frustrated ferromagnets have more helicity and vorticity degrees of freedom in compared with the skyrmion stabilized by DzyaloshinskiiMoriya Interaction (DMI). In this work, we attempted to model a system using micromagnetic simulation to induce frustration by taking RKKY interaction as perturbation in a Synthetic antiferromagnet (SAF). The frustration in the system could be due to the equivocation of DMI between two antiferromagnetically coupled layer. We not only found the existence of Q = 0 skyrmion, but also able to stabilize the skyrmion and antiskyrmion in the same layer. Later we deposited Ta/(Pt/Co)_2/Ir(x)/Co/Pt (x= 0.5 and 1.0 nm) on Silicon substrate using DC magnetron sputtering to optimize the SAF nature of the thin films and to observe the domain images using Kerr Microscope.  

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Alexey Tyukin, Mainz  
Momentum transfer reconstruction for the P2 Experiment  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Dr. Christian Smorra, Institut für Physik, JGU Mainz  
Precision measurements with antiprotons and transportable traps  

Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
Michael Wurm, Institut für Physik  
THEIA: Chertons, scintons and other new discoveries in lowenergy neutrino physics  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Professor Manfred Popp, Karlsruher Institut für Technologie  
Was Hitlers Atombombe verhinderte  Kernphysik während des 2. Weltkrieges  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik 12:00 Uhr s.t., NewtonRaum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) 
Stanislav Bodnar, Inst. f. Physik  
Manipulation of Néel vector in antiferromagnetic Mn2Au by current and magnetic field pulses  

TheoriePalaver
Institut für Physik 14:30 Uhr s.t., MITP Seminar Room 
Fabian Lange, RWTH Aachen  
The GradientFlow formalism was primarily introduced for simulations of Quantum Chromodynamics (QCD) on the lattice and has now found widespread use in this field. In addition, it offers the potential for crossfertilization between perturbative and lattice calculations.
In my talk I will introduce the GradientFlow formalism and outline the perturbative approach. Afterwards, I will present two examples of its applications. First, I will show how it could be used to extract the strong coupling constant from lattice simulations. As second application, I will illustrate how it helps to define the energymomentum tensor of QCD on the lattice.  

PRISMA Colloquium
Institut für Physik 13:00 Uhr s.t., LorentzRaum 05127, Staudingerweg 7 
Jonathan Butterworth, UCL London  
Particlelevel, differential measurements made in fiducial regions of phasespace at colliders have a high degree of modelindependence and can therefore be compared in a very generic way not only to precision Standard Model predictions, but to beyond the Standar Model physics implemented in Monte Carlo generators. This allows a wider array of final states to be considered than is typically the case, as well as a wider array of specific models, and optimises the longterm impact of precision LHC data. I present a method of exploiting this, with examples.
 

Seminar über Quanten, Atom und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., LorentzRaum (05127), Staudingerweg 7 
Prof. Dr. Philipp Haslinger, Atominstitut, TU Wien, Österreich  
Atom interferometry has proven within the last decades its surprising versatility to sense with high precision tiniest forces. In this talk I will give an overview of our recent work using an optical cavity enhanced atom interferometer to sense with gravitational strength for fifths forces [1,2] and for an on the firstplace counterintuitive inertial property of blackbody radiation [3].
Blackbody (thermal) radiation is emitted by objects at finite temperature with an outward energymomentum flow, which exerts an outward radiation pressure. At room temperature e. g. a cesium atom scatters on average less than one of these blackbody radiation photons every 10^8 years. Thus, it is generally assumed that any scattering force exerted on atoms by such radiation is negligible. However, particles also interact coherently with the thermal electromagnetic field [4] and this leads to a surprisingly strong force acting in the opposite direction of the radiation pressure [3].
If dark energy, which drives the accelerated expansion of the universe, consists of a light scalar field it might be detectable as a “fifth force” between normalmatter objects. In order to be consistent with cosmological observations and laboratory experiments, some leading theories use a screening mechanism to suppress this interaction. However, atominterferometry presents a tool to reduce this screening [5] on socalled chameleon models [6]. By sensing the gravitational acceleration of a 0.19 kg in vacuum source mass which is 10^8 times weaker than Earth´s gravity, we reach a natural bound for cosmological motivated scalar field theories and were able to place tight constraints [1,2].
[1] P. Hamilton, M. Jaffe, P. Haslinger, Q. Simmons, H. Müller, J. Khoury, Atominterferometry constraints on dark energy, Science. 349 (2015) 849–851.
[2] M. Jaffe, P. Haslinger, V. Xu, P. Hamilton, A. Upadhye, B. Elder, J. Khoury, H. Müller, Testing subgravitational forces on atoms from a miniature, invacuum source mass, Nat. Phys. 13 (2017) 938–942.
[3] P. Haslinger, M. Jaffe, V. Xu, O. Schwartz, M. Sonnleitner, M. RitschMarte, H. Ritsch, H. Müller, Attractive force on atoms due to blackbody radiation, Nat. Phys. 14 (2018) 257–260.
[4] M. Sonnleitner, M. RitschMarte, H. Ritsch, Attractive Optical Forces from Blackbody Radiation, Phys. Rev. Lett. 111 (2013) 23601.
[5] C. Burrage, E.J. Copeland, E.A. Hinds, Probing dark energy with atom interferometry, J. Cosmol. Astropart. Phys. 2015 (2015) 042–042. doi:10.1088/14757516/2015/03/042.
[6] B. Elder, J. Khoury, P. Haslinger, M. Jaffe, H. Müller, P. Hamilton, Chameleon dark energy and atom interferometry, Phys. Rev. D. 94 (2016) 44051.
 

SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 14:00 Uhr s.t., MAINZSeminarraum, Staudinger Weg 9, 03122 
Prof. Matthias Wuttig, RWTH Aachen University of Technology, Germany  
It has been a longtime dream of mankind to design materials with tailored properties. In recent years, the focus of our work has been the design of phase change materials for applications in data storage. In this application, a remarkable property portfolio of phase change materials (PCMs) is employed, which includes the ability to rapidly switch between the amorphous and crystalline state. Surprisingly, in PCMs both states differ significantly in their properties. This material combination makes them very attractive for data storage applications in rewriteable optical data storage, where the pronounced difference of optical properties between the amorphous and crystalline state is employed. This unconventional class of materials is also the basis of a storage concept to replace flash memory. This talk will discuss the unique material properties, which characterize phase change materials. In particular, it will be shown that only a welldefined group of materials utilizes a unique bonding mechanism (‘Bond No. 6’), which can explain many of the characteristic features of crystalline phase change materials. Different pieces of evidence for the existence of this novel bonding mechanism, which we have coined metavalent bonding, will be presented. In particular, we will present a novel map, which separates the known strong bonding mechanisms of metallic, ionic and covalent bonding, which provides further evidence that metavalent bonding is a novel and fundamental bonding mechanism. This insight is subsequently employed to design phase change materials as well as thermoelectric materials. Yet, the discoveries presented here also force us to revisit the concept of chemical bonds and bring back a history of vivid scientific disputes about ‘the nature of the chemical bond’.  

Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau Sonderseminar: 10:30 Uhr s.t., Newtonraum, 01122, Staudingerweg 9 
Philipp Arras, MPI Astrophysics, Garching  
Information field theory and applications in calibration and imaging algorithms  
Sonderseminar  

Seminar für Kern und Radiochemie
Institut für Kernchemie 16:00 Uhr s.t., Seminarraum Kernchemie 
Prof. Dr. Bernd Krause, Universität Rostock  
Thema folgt  

Institutsseminar Kern und Hadronenphysik
Institut für Kernphysik 14:00 Uhr s.t., HS Kernphysik, Becherweg 45 
Oliver Noll, Mainz  
Digital signal processing for the PANDA electromagnetic calorimeter  

Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum 
Christopher Hils, Insitut für Physik  
Ultralow energy calibration of the XENON1T detector with an internal 37Ar source  

Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:00 Uhr s.t., HS KPH 
Dr. Friederike Otto, ECI, University of Oxford  
COLLOQUIUM CANCELLED! Angry Weather How Climate Change is affecting extreme Weather around the World  
COLLOQUIUM CANCELLED! 
Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik 12:00 Uhr s.t., NewtonRaum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) 
Amrit R. Pokharel, Inst. f. Physik  
Carrier relaxation dynamics in Kondo insulator YbB12  

TheoriePalaver
Institut für Physik 14:30 Uhr s.t., MITP seminar room 
Avirup Ghosh, Harish Chandra Research Institute  
The existence of Dark Matter (DM) as one of the major component of our universe is inevitable today. Though there are several evidences of DM, all of them are gravitational in nature. The particle nature of DM is yet unknown. The most popular theory of particle DM is Weakly Interacting Massive Particles(WIMP) which though very interesting from the point of view of naturalness, is not yet tested in experiments. On the other hand, Feebly Interacting Massive Particles (FIMP) as an alternative scenario is gaining attention in recent times which due to their feeble interaction can not be observed in current generation of experiments. I shall discuss in my talk how in some FIMP scenarios the tiny coupling of FIMP DM give rise to interesting signals.  

SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 14:00 Uhr s.t., MAINZ Seminarraum, Staudinger Weg 9, 3. Stock, 03122 
Markus Garst, KIT Karlsruhe, Germany  
The weak DzyaloshinskiiMoriya interaction (DMI) in chiral magnets stabilizes spatially modulated magnetic textures like helices and skyrmion crystals. In this talk we focus on the dynamical properties of such textures. In the fieldpolarized phase of chiral magnets, the DMI results in a pronounced nonreciprocity of the magnon spectrum, i.e. the excitation energy is not symmetric with respect to an inversion of the wavevector. In the conical helix phase, the spin waves experience Bragg scattering off the periodic magnetic texture that leads to a backfolding of the magnon spectrum. As a result, the spectrum becomes reciprocal for wavevectors along the helix axes. However, the distribution of spectral weight in the spin structure factor remains nonreciprocal as confirmed by inelastic neutron scattering [1,2]. For wavevector with a finite perpendicular component of the wavevector, dipolar interactions induce a nonreciprocity which was detected by Brillouin light scattering [3]. We also discuss the spin wave spectrum of the skyrmion crystal phase where the nontrivial topology leads to an emergent electrodynamics for magnons. As a result the spectral weight of the spin structure factor is widely distributed at high energies. The spin wave excitations propagating along the skyrmion strings also exhibit a nonreciprocity as confirmed by spin wave spectroscopy [4]. Finally, we discuss the nonlinear dynamics of a single skyrmion string [5].  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik Sonderseminar: 15:15 Uhr s.t., MAINZ Seminarraum, Staudinger Weg 9, 3. Stock, 03122 
Kelvin van Hoorn, Technical University of Eindhoven, The Netherlands  
Magnetic field sensors based on deflection of membranes  
Sonderseminar  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik Sonderseminar: 15:00 Uhr s.t., MEDIENRaum, Staudinger Weg 7, 3. Stock, Raum 03431 
Chi Fang, University of Chinese Academy of Sciences, Beijing, China  
The application potential of spinorbittorques in magnetic random access memory attracts great attention and research interest in spinorbit coupling in heavy metals like Platinum and Tantalum. Thus the spin relaxation time τ_s, as a crucial parameter to investigate spin relaxation mechanism in the heavy metals, requires accurate and effective estimation. A traditional threeterminal method is also widely utilized to estimating τ_s of semiconductors and light metals. Its reliability, however, has recently been challenged by some experiments in which tunneling anisotropic magnetoresistance (MR) or spin blockage MR rather than the MR induced by spin injection and subsequent Hanle effect is more appropriate to explain the data.
In this talk, I will introduce the spininjectioninduced magnetoresistance of which the magnitude is comparable with other MR phenomena originating from the tunnel barrier is observable at room temperature as well as low temperatures in the second harmonic signals. Threeterminal and second harmonic method are combined in our measurement in Pt and Ta systems. Furthermore, we could estimate τ_s of heavy metals through fitting the signal with Lorentz function. This experimental approach make it possible to directly acquire τ_s of heavy metals with electrical method.  
Sonderseminar  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik Sonderseminar: 14:30 Uhr s.t., MEDIENRaum, Staudinger Weg 7, 3. Stock, Raum 03431 
Dr. Kunie Ishioka, National Institute for Materials Science, Tsukuba, Japan  
Mittwoch, den 19. Februar 2020 um 14:30
im MEDIENRaum, Staudinger Weg 7, 03431
Ultrafast Carrier and Phonon Dynamics of Hybrid Lead Halide Perovskite
Kunie Ishioka
National Institute for Materials Science, Tsukuba, Japan
Inorganicorganic hybrid lead halide perovskites, consisting of the soft lead halide octahedral framework and the organic molecular cations, are among the key materials for the next generation photovoltaics. In the first half of my talk I present on the charge separation dynamics at the interfaces of methylammonium lead iodide MAPbI3 with three different hole transport materials (HTMs) [1]. Here, the differential transmission signals revealed the hole injection from the perovskite to organic HTMs to occur on the time scale of 1 ps, whereas that to inorganic NiOx on an order of magnitude longer timescale. The anticorrelation with the fill factor of the solar cells suggests that the interfacial quality was responsible. In the second half I present our recent results on the coherent phonons of MAPbI3 [2]. We observe periodic modulations in the transient transmissivity due to the photoinduced libration and torsion of the methylammonium cations and the deformation of the PbI6 octahedral framework. The frequencies of the cation torsion and the octahedral deformations exhibited downchirps, in agreement with theoretically predicted strong anharmonicities of their vibrational potentials.  
Sonderseminar  
Sondertermin 
SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 14:15 Uhr s.t., MAINZ Seminarraum, Staudinger Weg 9, 3. Stock, 03122 
Shefali Vaidya, IRCELYON, Lyon, France  
Molecular magnets to phase changing coordination polymers: criteria an challenges for molecules for their potential application in memory storage  

SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 14:15 Uhr s.t., MAINZ Seminarraum, Staudinger Weg 9, 3. Stock, 03122 
Thomas Allison, Stony Brook University, NY, USA  
Timeresolved ARPES at 88 MHz repetition rate with full 2π collection  

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., Newtonraum, 01122, Staudingerweg 9 
Fabian Kössel, Institut für Physik  
Emerging patterns from the collective dynamics of microswimmers in an external field  
Trial PhD defense talk 
SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 14:00 Uhr s.t., Galilei seminar room (Staudinger Weg 9, room 01128) 
Mehrdad Elyasi, Tohoku University, Sendai, Japan  
Magnons for Quantum Information  

SFB/TR49/SFB TRR 173 Spin+XKolloquium/TopDyn  Seminar experimentelle Physik der kondensierten Materie
SFB/TR49  Prof. Dr. Elmers 14:00 Uhr s.t., MAINZ seminar room (Staudinger Weg 9, 3rd floor, room 03122) 
Dr. Aga Shahee, Seoul University  
Doping tunable multiferroicity in PbCu3TeO7 and magnetoelectric coupling in Van der Waal CuCrP2S6  

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., Newtonraum, 01122, Staudingerweg 9 
Jan Rothörl, Institut fuer Physik  
Creating 3D structures of diploid cells from HiC data using a Molecular Dynamics approach  
Master Colloquium 
Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik Sonderseminar: 11:00 Uhr s.t., MEDIENRaum, Staudingerweg 7, 3. Stock, Raum 431 
Jonas Knobel, Universität Würzburg  
New directions in spintronics heading towards devices based on antiferromagnetic materials require a fundamental understanding of the underlying physics. CuMnSb grown by molecular beam epitaxy (MBE) on GaSb substrates can provide a model system of a thin film antiferromagnet. I will report on the growth of virtually unstrained pseudomorphic single crystals showing clear antiferromagnetic behavior. The ordering temperature of CuMnSb between 50K and 62K lies well within the reach of standard cryostats. This allows to diff erentiate thermal from magnetic properties in transport devices.
I will first discuss the epitaxial growth of a GaSb buff er layer needed for a sharp interface. Subsequent CuMnSb growth is highly dependent on the flux ratios of the respective elements. I will explain their influence on crystal properties and how reflection highenergy electron di ffraction (RHEED) is used to control the growth process.  
Sonderseminar  

Seminar Festkörper und Grenzflächenphysik KOMET  experimentell
Institut für Physik Sonderseminar: 14:00 Uhr s.t., MEDIENRaum, Staudingerweg 7, 3. Stock, Raum 431 
Kanji Furuta, Department of Materials Science and Engineering, Nagoya University, Japan.  
MAX phase compounds have recently attracted much attention due to their possible application to the production of a new class of twodimensional systems called MXenes [1]. Mo4Ce4Al7C3 is affiliated with the MAX phase and in a family of REbased nanolaminates with a chemical formula of Mo4RE4Al7C3. From magnetization measurements, xray absorption nearedge structure (XANES), and xray magnetic circular dichroism (XMCD), a ferromagnetism below a Curie temperature of TC ~ 10.5 K and a mixedvalence states of the Ce 4f electrons have been reported [2].
To understand the origin of electronic/magnetic properties of Mo4Ce4Al7C3, we have performed angleresolved photoemission spectroscopy (ARPES) on Mo4Ce4Al7C3 singlecrystals. As a result, we have succeeded to obtain the electronic band structure as well as Fermi surface of this system. From the comparison between Ce 4d4f on and off resonant ARPES, strong Ce 4f character at the electron pocket around the G point has been elucidated. Furthermore, we have found a clear increase of the Ce 4f spectral weight below TC. The results suggest that itinerant Ce 4f electrons may play an important role in the magnetic properties of Mo4Ce4Al7C3.
REFERENCES
[1] M. Barsoum, MAX phases (Wiley, Weinheim, 2013).
[2] Q. Tao et al., Phys. Rev. Mat. 2, 114401 (2018).  
Sonderseminar  
