Aktuelle Veranstaltung für 21 Nov 2024

Prof. Dr. David Hunger, KIT (Karlsruher Institut für Technologie)

Optically addressable spins in the solid state are promising candidates for realizations of quantum networks and quantum computing nodes. We study NV centers in diamond coupled to an optical microcavity to enhance the optical emission and get efficient access to the spin degree of freedom. Studying small ensembles, we observe collectively enhanced emission and non-trivial photon statistics, despite the presence of inhomogeneities and spatial separation between emitters [1]. As an alternative color center, we study SnV centers in diamond, which can possess superior optical coherence properties. We observe hour-long spectral stability and Fourier-limited emission linewidths of individual emitters. We leverage their spin degree of freedom by studying a strained diamond at mK temperature. To avoid Ohmic losses in the microwave line, we fabricate a superconducting coplanar waveguide on a diamond membrane. We demonstrate coherent manipulation of the electron spin and evaluate the decoherence properties for different magnetic field orientations at mK temperature [2]. We furthermore identify strongly coupled nuclear spins and achieve nuclear spin state preparation and coherent control. Prospects for integration into a microcavity for efficient spin-photon interfacing are discussed [3]. A complementary platform is rare earth ion-based materials. I will report investigations of molecular rare-earth-complexes with promising coherence properties for quantum applications [4] and efforts to study single ions coupled to a cavity as qubits [5]. References [1] Pallmann et al., arxiv:2311.12723 [2] Karapatzakis et al., Phys Rev X 14, 031036 (2024) [3] Körber et al., Phys Rev Appl. 19, 064057 (2023) [4] Serrano et al., Nature 603, 241 (2022) [5] Deshmukh et al., Optica 10, 1339 (2023)

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

14:15 Uhr s.t., IPH Lorentzraum 05-127

Vincent Jeudy, Laboratoire de Physique des Solides, CNRS, Université Paris-Saclay, 91405 Orsay Cedex, France.

The controlled displacement of spin textures as magnetic domain walls (DWs) is at the basis of potential applications to magnetic memory storage, neuromorphic computation... However, DWs are very sensitive to weak pinning defects, which strongly reduce their mobility and produce roughening and stochastic avalanche-like motion. The interplay between weak pinning disorder, DW elasticity, thermal fluctuations and an external drive leads to universal dynamical behaviors also encountered for interfaces in ferroelectrics, contact lines in wetting, bacterial colonies, failure propagation... In this variety of physical systems, the interfaces are expected to present both universal [1] and non-universal (material and temperature) behaviors, which are particularly important to disentangle for understanding the pinning dependent dynamics. In this talk, I will discuss a set of recent studies, which reveal the universal scaling functions accounting for both drive and thermal effects on the depinning and thermally activated creep motion [1] of DWs in thin ferromagnetic films with perpendicular anisotropy. Interestingly a self-consistent phenomenological model describing both the creep and depinning dynamics allows to compare the pinning properties of different materials [2], to address the interaction between DWs and pinning disorder [3] and to analyze the dynamics of other magnetic texture as skyrmions [4]. [1] V. Jeudy et al., Phys. Rev. Lett. 117, 057201 (2016); R. Diaz Pardo et al., Phys. Rev. B 95, 184434 (2017); R. Diaz Pardo et al., Phys. Rev. B 100, 184420 (2019); L. J. Albornoz et al., Phys. Rev. B 110, 024403 (2024) [2] V. Jeudy et al., Phys. Rev. B 98, 054406 (2018) [3] P. Géhanne et al., Phys. Rev. Res. 2, 043134 (2020); C. Balan et al., Appl. Phys. Lett. 122, 162401 (2023) [4] S. Mallick et al., Nat. Commun 15, 8472 (2024)

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

14:00 Uhr s.t., 01 122 Newton-Raum


Wochenübersicht für die Woche 18 Nov 2024 bis 24 Nov 2024 (KW 47)

19 Nov 2024

Physikalisches Kolloquium

Institut für Physik

16:15 Uhr s.t., HS KPH

Jordi Jose, Universitat Politècnica de Catalunya
Stellar evolution and the origin of cosmic elements constitute a truly multidisciplinary arena that combines tools, developments and achievements in theoretical astrophysics, observational astronomy, cosmochemistry and nuclear physics: supercomputers have provided astrophysicists with the required computational capabilities to study the evolution of stars in a multidimensional framework; the emergence of high-energy astrophysics with space-borne observatories has opened new windows to observe the Universe, from a novel panchromatic perspective; cosmochemists have isolated tiny pieces of stardust embedded in primitive meteorites, giving clues on the processes operating in stars as well as on the way matter condenses to form solids; and nuclear physicists are measuring reactions near stellar energies, using stable and radioactive ion beams. This talk will provide a comprehensive insight into the physics of stellar explosions, with particular emphasis on some recent advances in the modeling of type Ia supernovae, classical and recurrent novae, and type I X-ray bursts.

Theorie-Palaver

Institut für Physik

14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor)

Konstantin Asteriadis, University of Regensburg
We systematically study potential effects of BSM physics in the e+ e- -> Z H process. To this end, we include all relevant dimension-6 Standard Model Effective Field Theory operators and work to next-to-leading order (NLO) accuracy in the electro-weak coupling. We consider both polarized and unpolarized electron and positron beams and present results for $\sqrt{s}$=240, 365 and 500~GeV and emphasize observables where the NLO predictions differ significantly from the leading order (LO) results. At NLO, a sensitivity arises to operators that do not contribute at tree level, such as the Higgs trilinear coupling , CP violating operators, dimension-6 operators involving the top quark or anomalous Higgs-Z boson couplings, among many others. We compare the prospects of future e+e- colliders to explore these new physics effects with measurements from the LHC, electron EDMs (for CP violating operators), and Z pole measurements.

20 Nov 2024

PRISMA+ Colloquium

Institut für Physik

13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7

Prof. Dr. Ilaria Brivio, University of Bologna, Italy
The talk will give an overview of LHC probes of Axion-Like Particles (ALPs), whose couplings are parameterized via effective interactions of dimension larger than 5. The first part will introduce the main motivations for studying ALPs and it will discuss the main properties of the ALP EFT, while the second will be dedicated to phenomenological aspects. This will contain a general overview of how ALPs can be searched at colliders, as well as brief discussions of theory constraints stemming from perturbative unitarity and of recent new ideas brought forward in the field, such as the use of non-resonant ALP production in constraining ALP couplings to heavy SM states, and the exploration of ALP couplings beyond dimension-5.

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

F. Schmid / G. Settanni / P. Virnau / L. Stelzl

10:15 Uhr s.t., Hilbert-Raum, 05-426, Staudingerweg 9

Alexander Kurganov, Prof. Dr.
I will present semi-discrete path-conservative central-upwind (PCCU) schemes for ideal and shallow water magnetohydrodynamics (MHD) equations. These schemes possess several important properties: they locally preserve the divergence-free constraint, they do not rely on any (approximate) Riemann problem solver, and they robustly producehigh-resolution and non- oscillatory results. The derivation of the schemes is based on the Godunov-Powell nonconservative modifications of the studied MHD systems. The local divergence-free property is enforced by augmenting the modified systems with the evolution equations for the corresponding derivatives of the magnetic field components. These derivatives are then used to design a special piecewise linear reconstruction of the magnetic field, which guarantees a non- oscillatory nature of the resulting scheme. In addition, the proposed PCCU discretization accounts for the jump of the nonconservative product terms across cell interfaces, thereby ensuring stability. I will also discuss the extension of the proposed schemes to magnetic rotating shallow water equations. The new scheme is both well-balanced and exactly preserves the divergence- free condition of the magnetic field. The well-balanced property is enforced by applying a flux globalization approach within the PCCU scheme. As a result, both still- and moving- water equilibria can be exactly preserved at the discrete level. The proposed PCCU schemes are tested on several benchmarks. The obtained numerical results illustrate the performance of the new schemes, their robustness, and their ability not only to achieve high resolution, but also preserve the positivity of computed quantities such as density, pressure, and water depth. The talk is based on joint works with Alina Chertock (North Carolina State University, USA), Michael Redle (RWTH Aachen University, Germany),Kailiang Wu (Southern University of Science and Technology, China) and Vladimir Zeitlin (Sorbonne University, France).

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

JGU

13:00 Uhr s.t., 01 122 Newton-Raum

Dong-Soo Han, Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul 02456, Republic of Korea
Spintronics has emerged as a promising field for the development of energy-efficient magnetic memory and logic devices by controlling spin states in ferromagnets via spin-orbit coupling1,2. Efficient control of magnetization in ferromagnets is crucial for high-performance spintronic devices, and magnons have gained renewed interest as a potential avenue for achieving this goal with reduced Joule heating and minimized power consumption. In pursuit of this objective, Previous efforts have focused on optimizing magnon transport with minimal dissipation under the belief that dissipation hinders efficient magnetization control. In contrast, we present an unconventional approach that harnesses magnon dissipation for magnetization control instead of suppressing it. Our approach involves a heterostructure consisting of a ferromagnetic metal and an antiferromagnetic insulator, exploiting an intrinsic spin current within the ferromagnetic metal3,4. By combining a single ferromagnetic metal with an antiferromagnetic insulator that breaks spin transport symmetry while preserving charge transport symmetry, we achieve significant spin-orbit torques comparable to those observed in non-magnetic metals, enabling magnetization switching. Through systematic experiments and comprehensive analysis, we confirm that our findings arise from magnon dissipation within the AFI rather than external spin sources. These results provide novel insights into the mechanisms of spin current generation and dissipation, opening up new possibilities for developing energy-efficient spintronic devices. Reference 1. Sinova, J. et al. Rev. Mod. Phys. 87, 1213–1260 (2015). 2. Shao, Q. et al. IEEE. Trans. Magn. 57, 1–39 (2021). 3. Hibino, Y. et al. Nat. Commun. 12, 6254 (2021). 4. Wang, W. et al. Nat. Nanotechnol. 14, 819–824 (2019).

zukünftige Termine
22 Nov 2024

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

F. Schmid / G. Settanni / P. Virnau / L. Stelzl

14:15 Uhr s.t., Hilbert room, 05-426, Staudingerweg 9

Alina Chertock, Prof. Dr.
Many important scientific problems involve several sources of uncertainties, such as model parameters and initial and boundary conditions. Quantifying these uncertainties is essential for many applications since it helps to conduct sensitivity analysis and provides guidance for improving the models. The design of reliable numerical methods for models with uncertainties has seen a lot of activity lately. One of the most popular methods is Monte Carlo-type simulations, which are generally good but inefficient due to the large number of realizations required. In addition to Monte Carlo methods, a widely used approach for solving partial differential equations with uncertainties is the generalized polynomial chaos (gPC), where stochastic processes are represented in terms of orthogonal polynomials series of random variables. It is well-known that gPC- based methods, which are spectral-type methods, exhibit fast convergence when the solution depends smoothly on random parameters. However, their application to nonlinear systems of conservation/balance laws still encounters some significant difficulties. The latter is related to the presence of discontinuities that may develop in numerical solutions in finite time, triggering the appearance of aliasing errors and Gibbs-type phenomena. This talk will provide an overview of numerical methods for models with uncertainties and explore strategies to address the challenges encountered when applying these methods to nonlinear hyperbolic systems of conservation and balance laws.

Zum Physikalischen Kolloquium Mainz


Liste der laufenden Seminare und Kolloquien

Veranstaltungstitel Termin und Ort Koordinator
Institutsseminar Kern- und Hadronenphysik Montags, 1415 Uhr, HS Kernphysik, Becherweg 45 Prof. Dr. Michael Ostrick
Seminar Festkörper- und Grenzflächenphysik Dienstags, 1200 Uhr, Newton-Raum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebaeude) Prof. Dr. Hans-Joachim Elmers
Seminar über Theorie der Kondensierten Materie/
Weiche Materie und Statistische Physik
Freitags, 1030 Uhr, Newton-Raum (LG 01-122) F. Schmid
P. Virnau
L. Stelzl
Theory of Condensed Matter: Hard Condensed Matter Tuesday, 1000 Uhr, Seminarraum K Prof. Dr. Jairo Sinova
Theorie Palaver Dienstags, 1430 Uhr, Lorentz-Raum (05-127) Upalaparna Banerjee
Federico Gasparotto
Pouria Mazloumi
Yong Xu
Physikalisches Kolloquium Mainz Dienstags, 1615 Uhr, HS Kernphysik, Becherweg 45 Prof. Dr. Friederike Schmid
Prof. Dr. Concettina Sfienti
PRISMA Colloquium Mittwochs, 1300 Uhr, Lorentz-Raum (05-127) Prof. Dr. Tobias Hurth
Quantengravitation-Seminar Donnerstags, Sozialraum der THEP; Institut fuer Physik (05-427). Prof. Dr. M. Reuter
Theoriekolloquium Donnerstags, 1600 Uhr, Newton-Raum (LG 01-122). Prof. Dr. P.G.J. van Dongen
Jun.-Prof. Dr. J. Marino
QUANTUM-Seminar Donnerstags, 1415, Lorentz-Raum (05-127) Prof. Dr. Peter van Loock
Dr. Lars von der Wense
Seminar experimentelle Physik der kondensierten Materie Donnerstags, 1400, Minkowski-Raum, 05-119, Staudingerweg 7 Univ-Prof. Dr. Jure Demsar
Univ.-Prof. Dr. Hans-Joachim Elmers
Univ.-Prof. Dr. Mathias Kläui
Univ.-Prof. Dr. Thomas Palberg
Seminar zu Themen in der Collider-Physik Freitags, 1230, Sozialraum ThEP (05-427) Riccardo Bartocci
Prisco Lo Chiatto
Nicklas Ramberg
Miroslava Mosso Rojas
MAINZ lecture series Mittwochs, 915, Staudingerweg 9, 3. Stock, Raum 122 Dr. M. Weides
Excellence@WORK XXXXX,XXXX Katrin Klauer
Seminar about Experimental Particle and Astroparticle Physics (ETAP) Montags, 1215, Staudingerweg 7, 5. Stock, Minkowski-Raum 119 Dr. DB. Ta

Weitere Veranstaltungen

Quantum Sonderseminar Seminarraum Quantum (02-427) Prof. Dr. Ferdinand Schmidt-Kaler

 

Beteiligte Einrichtungen: Institut für Physik,
Institut für Kernphysik,
Institut für Physik der Atmosphäre
Max-Planck-Institut für Polymerforschung, Max-Planck-Institut für Chemie
Technische Wartung: ducbao.ta (klammeraffe) uni-mainz.de