Jahresübersicht für das Jahr 2024
09 Jan 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Markus Roth, TU Darmstadt | |
With the recent demonstration of fusion ignition and burn and the first energy gain from controlled fusion reactions, the laser-based fusion approach has become a promising concept for fusion energy. While not supported in Germany until a few years ago, Germany has a huge potential in taking the lead on laser-fusion research, based on its excellent science and technology in optics and lasers.
Focused Energy is a US/German Startup company, spin-off of the TU Darmstadt that has gathered the world experts in laser fusion in the last two years.
I will review the recent results at the Lawrence Livermore National Laboratory National Ignition Facility and sketch a pathway from this groundbreaking result to a first fusion reactor prototype. Slides here... | |
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Seminar Festkörper- und Grenzflächenphysik KOMET - experimentell
Institut für Physik 12:00 Uhr s.t., Newton-Raum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) |
| TBA, TBA | |
TBA | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Zeno Capatti, U. Bern | |
In this talk, I will review the main aspects of three-dimensional approaches to the computation of Feynman diagrams and of the Local Unitarity formalism. I will start by discussing the Cross-Free Family representation, which allows for a systematic analysis of the singularities of Feynman diagrams. I will then introduce the Local Unitarity framework, in which interference diagrams are combined, through a generally-applicable mapping of the phase-space measure, to give locally finite cross-sections. Finally, I will discuss the extension of the Local Unitarity formalism to processes with initial state singularities, which will allow me to discuss the role of spectator particles and higher-multiplicity initial-state partonic configurations in the cancellation and factorisation of singularities. | |
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10 Jan 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Andrea Caputo, CERN, Switzerland | |
All the burning questions of the Standard Model such as the origin of dark matter, of the matter antimatter asymmetry, of neutrino masses, seem to invoke the presence of other, “dark” particles. But how do we look for these new particles? In this talk I advocate for the use of astrophysical objects as a laboratory to make progress on these puzzles. In particular, the referent will describe some ideas to use Supernovae and galaxy observations with line intensity mapping to shed some light on this darkness and probe motivated models such as axion-like particles, dark photons, light CP-even scalars. This effort is very timely, as it coincides with a broad set of astrophysical and cosmological observations becoming available now and in the near future. | |
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11 Jan 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Dr. Stefan Eriksson, Department of Physics, Faculty of Science and Engineering, Swansea University, UK | |
Precision measurements of the properties of trapped antihydrogen offer stringent tests of fundamental principles underlying particle physics and general relativity, such as Lorentz and CPT invariance and the Einstein Equivalence Principle. In this presentation I will give an overview of the ALPHA antihydrogen experiment at CERN including recent results from spectroscopy and observations of the effect of gravity. I will review how results are interpreted as tests of fundamental physics with a discussion of how a hypothetical CPT violation could result in matter-antimatter asymmetry. I will give an outline of the prospects for future high-precision spectroscopy, free-fall and gravitational redshift experiments with antihydrogen. | |
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15 Jan 2024
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Johann Martyn, Institut für Physik | |
Deployment of Water-based Liquid Scintillator in ANNIE | |
| at https://indico.him.uni-mainz.de/event/199/ | |
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16 Jan 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Marco Durante, GSI Helmholtzzentrum für Schwerionenforschung GmbH | |
Particle therapy is a rapidly growing and potentially the most effective and precise radiotherapy technique. However, only a tiny minority of patients receive protons or heavy ions rather than X-rays these days. Physics research is needed to address a few problems that hamper its wider diffusion. The efforts are toward making particle therapy cheaper, faster, and more conformal.
In this lecture we will give some examples of applications of nuclear physics to particle therapy. In particular, for reducing range uncertainty we will discuss the use of radioactive ion beams (RIBs) for simultaneous treatment and online range verification using positron emission tomography (PET) within the ERC AdG BARB (Biomedical Applications of Radioactive ion Beams) project at GSI/FAIR. We will also report on recent experiments in collaboration with Helmholtz Institute Mainz. Slides here... | |
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Seminar Festkörper- und Grenzflächenphysik KOMET - experimentell
Institut für Physik 12:00 Uhr s.t., Newton-Raum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) |
| TBA, TBA | |
TBA | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Álvaro Pastor Gutiérrez, MPIK Heidelberg | |
While the Standard Model of particle physics has been extremely successful in predicting experimental results, it still leaves us with unanswered questions about dark matter, the imbalance between matter and antimatter, and the emergence of fundamental scales. In this talk, I will outline our initial efforts to explore strong new physics scenarios using the non-perturbative functional renormalisation group. I will begin by introducing the flow equation and applying it to the Standard Model, thereby uncovering previously uncharted high-energy phases in the Higgs potential. The second part of the talk will focus on a comprehensive study of (quasi-)conformal “Technicolour” theories, aiming to identify Higgs-like bound states and detectable dark sectors. To achieve this, we will employ bosonisation techniques, which provide valuable insights into the properties of dynamically emergent bound states. I will conclude with a specific case study addressing the flavour puzzle within the framework of fundamental partial compositeness. | |
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17 Jan 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Stephan Dolan, CERN, Switzerland | |
Accelerator-based neutrino oscillation experiments have the potential to revolutionise our understanding of fundamental physics, offering an opportunity to characterise charge-parity violation in the lepton section, to determine the neutrino mass ordering and to explore the possibility of physics beyond three-flavour neutrino mixing. However, as more data is collected the current and next-generation of experiments will require increasingly precise control over the systematic uncertainties within their analyses. It is well known that some of the most challenging uncertainties to overcome stem from our uncertain modelling of neutrino-nucleus interactions, arising because measured event rates depend on the neutrino interaction cross section in addition to any oscillation probability. The sources of these uncertainties are often related to subtle details of the pertinent nuclear physics, such as the details of the target nucleus ground state, which are extremely difficult to control with sufficient precision. Confronting such uncertainties requires both state-of-art theoretical modelling and precise measurements of neutrino interaction event rates at experiment's near detectors, before oscillations occur. In this talk, we review the role of neutrino interaction systematic uncertainties in current and future measurements of neutrino oscillations as well as the experimental and theoretical prospects for reducing them to an acceptable level for the next generation of experiments. | |
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18 Jan 2024
GRK 2516 Soft Matter Seminar
Uni Mainz 14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Sofia Kantorovich, Computational Physics, University of Vienna | |
TBA | |
| at Zoom | |
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Seminar über Theorie der kondensierten Materie / TRR146 Seminar
F. Schmid / G. Settanni / P. Virnau / L. Stelzl 14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Sofia Kantorovich, Computational Physics, University of Vienna | |
GRK 2516 Soft Matter Seminar | |
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23 Jan 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| CANCELED: Prof. Jonathan Wurtele, University of Berkeley, California | |
This talk has been canceled due to illness!
The ALPHA Collaboration at CERN synthesizes, traps, and investigates the properties of antihydrogen, the antimatter equivalent of hydrogen. ALPHA’s research has the goal of testing the standard model which holds that antihydrogen and hydrogen have the same spectrum, and the prediction of general relativity that antihydrogen atoms experience the same gravitational force as hydrogen atoms do. ALPHA’s experiments conducted over the last decade produced measurements of the 1S-2S line, hyperfine structure, Lyman-alpha transition, and charge neutrality of antihydrogen. This presentation will predominantly delve into our latest breakthrough. Utilizing an innovative magnet system, we have successfully observed, for the first time, the interaction of neutral antimatter with the Earth’s gravitational field. The best fit to our measurements yields a value of (0.75 ± 0.13 (stat. + syst.) ± 0.16 (simulation)) g for the local acceleration of antimatter towards the Earth, consistent with the predictions of general relativity. We rule out the possibility of antihydrogen experiencing an upwards acceleration g in the Earth’s gravity. Finally, potential paths to higher-precision gravity experiments will be discussed. | |
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Seminar Festkörper- und Grenzflächenphysik KOMET - experimentell
Institut für Physik 12:00 Uhr s.t., Newton-Raum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) |
| TBA, TBA | |
TBA | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Daniel Schmitt, Frankfurt U. | |
Theories beyond the Standard Model (BSM) with classical scale invariance predict an intriguing thermal history of the early Universe. Due to the absence of dimensionful terms at tree level in these models, the electroweak phase transition (EWPT) can be significantly delayed, inducing a period of thermal inflation supercooling the Universe. The exit from this supercooled state can then be triggered via different mechanisms, depending on the model parameter space.
In the first part of my talk, I will discuss the end of supercooling via a strong, first-order QCD chiral phase transition. I will outline how the associated gravitational wave (GW) production can be studied within effective QCD theories, with a particular focus on the effect of thermal inflation on the strongly coupled dynamics.
In the second part, I will present an additional option to realize the exit from supercooling: a tachyonic phase transition. Here, the SM quark condensates source an exponential amplification of BSM scalar fields, generating a unique GW background detectable by future observatories. | |
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24 Jan 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Kai Schmitz, Univ. Münster | |
Pulsar Timing Array (PTA) collaborations around the globe recently announced compelling evidence for low-frequency gravitational waves permeating our entire Universe, that is, a gravitational-wave background (GWB) reaching us from all directions and at all times. This breakthrough achievement has important implications for astrophysics, as the GWB signal, if genuine, is likely to originate from a cosmic population of supermassive black holes orbiting each other at the centers of galaxies. As the referent will illustrate in this talk, the new PTA data is, however, also of great interest to the high-energy physics community, as it allows to probe a broad range of particle physics models of the early Universe that predict the generation of a cosmological GWB in the Big Bang. In this sense, the PTA data opens a new window onto the very early Universe and enables particle physicists to constrain scenarios of new physics beyond the Standard Model at extremely high energies. In his talk, the referent will give an overview of these searches for new physics at the PTA frontier and highlight several cosmological scenarios that underline the relevance of PTA observations for fundamental problems such as dark matter, neutrino masses, and the matter-antimatter asymmetry of the Universe. Finally, he will conclude with a brief outlook on future measurements that may help in discriminating between a GWB signal of astrophysical origin and a GWB signal from the Big Bang. Slides here... | |
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25 Jan 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Dr. Aleksandra Zoilkowska, JGU NEUQUAM Research Group | |
Cold atom experiments offer a distinctive platform for the investigation of many-body quantum physics, especially in non-equilibrium scenarios. The complexity inherent in these experiments often poses challenges to conventional theoretical methods. Nevertheless, exact analytical solutions become feasible when the underlying theory is integrable. Integrability plays a pivotal role in constraining the dynamics of many-body systems, enabling the derivation of, for instance, precise time-dependent density and velocity profiles after inhomogeneous quenches. This unique characteristic establishes a direct correspondence between theoretical predictions and experimental outcomes.
In this talk, I will delve into the essence of quantum integrability and its efficacy in non-equilibrium many-body calculations, utilizing the framework of Generalized Hydrodynamics. An examination of the Lieb-Liniger Hamiltonian will exemplify how integrability has been applied in cold atom setups, resulting in the experimental realization of Quantum Newton's Cradle. Furthermore, I will draw upon my own research to provide insights into other quantum ''beasts'' emerging in out-of-equilibrium physics, rooted in an integrable theory known as the Homogeneous Sine-Gordon Model. | |
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26 Jan 2024
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
F. Schmid / G. Settanni / P. Virnau / L. Stelzl 10:15 Uhr s.t., Lorentz Room, 05-127, Staudingerweg 7 |
| Scott Milner, Penn State University | |
Using simulations to predict miscibility | |
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29 Jan 2024
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Anamika Aggarwal, Institut für Physik | |
Phase-I Upgrade of the ATLAS Level-1 Calorimeter Trigger | |
| at https://indico.him.uni-mainz.de/event/199/ | |
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30 Jan 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Silvia Masciocchi, Heidelberg/GSI | |
Very high energy densities are reached in ultra-relativistic collisions of heavy ions. Under these conditions, the confinement in strongly-interacting matter is lifted, and a quark-gluon plasma (QGP) is formed. At the highest temperatures realized in the laboratory, this system offers us the opportunity to study QCD matter under extreme conditions. The successful heavy-ion program at the LHC provides data of increasing precision. I will illustrate how experimental evidence supports the description of the QGP by fluid dynamics. This has been recently extended to include even rare and penetrating probes such as heavy quarks. Through this description and making use of neural networks and Bayesian inference, we are able to determine fundamental properties of QCD with increasing precision. A quick look into the formidable detectors with which we gain this evidence in the ALICE will complete the overview. Slides here... | |
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Seminar Festkörper- und Grenzflächenphysik KOMET - experimentell
Institut für Physik 12:00 Uhr s.t., Newton-Raum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) |
| TBA, TBA | |
TBA | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Maria Ramos, IFT Madrid | |
Singlet scalars, namely axion-like particles (ALPs), are among the most promising candidates of new physics. Standard (minimal) assumptions in the study of these particles might however hide a large landscape of solutions to different puzzles in the Standard Model, which can limit our discovery potential. In the first part of the talk, I will consider the impact of scalar mixing in the standard axion mechanism to solve the strong CP problem. I will show that the canonical axion mass-scale relation can be modified within QCD and multiple signals may be required to reconstruct the full solution to the strong CP problem, constrained by a precise sum rule. In the second part of the talk, I will discuss the impact of operator mixing, via RGEs, in the ALP parameter space. I will specially focus on shift-breaking and CP violating effects, and I will discuss some phenomenological applications. | |
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31 Jan 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., MITP seminar room, Staudingerweg 9, 02-430 |
| Noah Fleischer, LUB Mannheim | |
Mixed teams have greater collective knowledge, better ideas and fewer sick days. In short: more success. However, diverse teams also have different perspectives and are therefore more complex to manage. Professors often reach their limits with traditional management styles. This is because stereotypes relating to gender, age and social background persist and hinder equality.
This leadership workshops deals with facts and figures on the topic of diversity & leadership in the university landscape - Anchoring diversity measures in daily university processes - Strategic leadership and teaching behavior using linguistic reframing techniques - Development of individually tailored measures for everyday life.
Noah Fleischer combines his many years of experience in international management consulting in the corporate, political, and academic sectors with expertise as a university lecturer in advanced analytics and AI application development. He also advocates for the integration of diversity into the sustainability strategy and EU taxonomy. Noah Fleischer is also active as a mentor in the Friedrich Ebert Foundation and UN speaker on the topic of gender lens investing.
All professors and group leaders are welcome. Please note that registration is required at prisma@uni-mainz.de until January, 10. | |
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01 Feb 2024
GRK 2516 Soft Matter Seminar
Uni Mainz 17:00 Uhr s.t., TU Darmstad (Room, TBA) |
| Günter Auernhammer, Leibniz Institute for Polymer Research, Dresden | |
TBA | |
| at Zoom | |
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Seminar über Theorie der kondensierten Materie / TRR146 Seminar
F. Schmid / G. Settanni / P. Virnau / L. Stelzl 14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Günter Auernhammer, Leibniz Institute for Polymer Research, Dresden | |
GRK 2516 Soft Matter Seminar | |
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Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Piet van Duppen, KU Leuven, Belgien | |
The thorium-229 nucleus contains an isomeric state with a low excitation energy, making it possible to probe using lasers. It is one of the best candidates for the development of a nuclear clock [1,2] which will enable the ability to test fundamental principles in physics (see e.g. [4]). However, to accomplish such a nuclear clock, the nuclear properties of the isomer need to be determined more precisely and two approaches are being followed.
VUV spectroscopy revealed the radiative decay of the thorium-229 isomer in a study at ISOLDE-CERN by populating the isomer via the beta decay of actinium-229, implanting the beam in large bandgap crystals (CaF2 and MgF2). A reduced uncertainty of the isomer’s excitation energy (8.338±0.024 eV) and a first determination of the half-life (670±102 s) in MgF2 was reported [5]. During a follow-up campaign, different crystals were tested, the energy was determined with a better precision and the half-life behaviour of the VUV signal in the different crystals was studied.
Preparatory work to perform laser ionization spectroscopy of the thorium-229 ground and isomeric states, populated in the alpha decay of uranium-233, is performed in an argon gas-jet based system. These studies, aimed to deduce the mean-square charge radii and moments of both ground and isomeric state, are based on singly charged thorium ions and necessitates a search for efficient and effective laser ionization schemes of thorium giving rise to a more precise determination of the first and second ionization potential. Results from these off and on-line studies will be presented and outlook to future work discussed.
[1] E. Peik and C. Tamm, EPL 61, 181 (2003).
[2] C. Campbell et al., Phys. Rev. Lett. 108, 120802 (2012).
[3] L. von der Wense et al. Nature 533 (7601), 47–51 (2016).
[4] E. Peik et al., Quantum Sci. Technol. 6, 034002 (2021).
[5] Kraemer et al., Nature 617, 706–710 (2023). | |
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Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 14:00 Uhr s.t., 01 122 Newton-Raum |
| Huaiyang YUAN, TU Delft and Zhejiang University | |
There is a rising interest in integrating magnetic systems with known quantum platforms for multi-functional quantum information processing. The coupling among magnons, photons, phonons, and qubits has already been proposed and demonstrated in the experiments. In this talk, I will introduce our recent results on the interplay of magnons and surface plasmons in two-dimensional systems. Our findings may open a novel route to integrate plasmonic and spintronic devices and bridge the fields of low-dimensional physics, plasmonics, and spintronics. | |
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06 Feb 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. J.C. Seamus Davis, University of Oxford | |
Everything around us, everything each of us has ever experienced, and virtually everything underpinning our technological society and economy is governed by quantum mechanics. Yet this most fundamental physical theory of nature often feels as if it is a set of somewhat eerie and counterintuitive ideas of no direct relevance to our lives. Why is this? One reason is that we cannot perceive the strangeness (and astonishing beauty) of the quantum mechanical phenomena all around us by using our own senses.
I will describe the history of development of techniques that allow us to visualize electronic quantum phenomena and new states of quantum matter directly at the atomic scale. As recent examples, we will visually explore the previously unseen and very beautiful forms of quantum matter making up electronic liquid crystals[1,2], high temperature superconductors[2,3,4] and electron-pair crystals[5,6,7,8]. I will discuss the implications for fundamental physics research and also for advanced materials and new technologies, arising from quantum matter visualization.
References:
1. Science 344, 612 (2014)
2. Nature 570, 484 (2019)
3. Science 357, 75 (2017)
4. Science 364, 976 (2019)
5. Nature 571, 234 (2020)
6. Nature 532, 343 (2016)
7. Science 372, 1447 (2021)
8. Nature 618, 921 (2023) Slides here... | |
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Seminar Festkörper- und Grenzflächenphysik KOMET - experimentell
Institut für Physik 12:00 Uhr s.t., Newton-Raum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude) |
| TBA, TBA | |
TBA | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Filippo Sala, U. Bologna | |
I will show how first order phase transitions (PT) in the early universe, with relativistic bubble walls, constitute particle accelerators and colliders via the dense shell of particles that they necessarily accumulate. These `bubbletrons' offer novel opportunities of observational access to very high energy scales, in addition to the gravitational waves from the PT. As three examples, I will discuss: i) non-adiabatic production of ZeV dark matter which is hot enough to leave an imprint in the matter power spectrum; ii) production of relics beyond the GUT scale without the need for the universe to ever reach those temperatures; iii) realization of testable baryogenesis and leptogenesis down to the TeV scale. In passing I will mention open questions about the physics of particle shells at bubble walls, and their potential far-reaching implications. | |
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07 Feb 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Martin Fertl, JGU Mainz, Institut für Physik, QUANTUM | |
Please see attachment Slides here... | |
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08 Feb 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. J.C. Séamus Davis, University of Oxford, Oxford, UK | |
Although UTe2 appears to be the first 3D spin-triplet topological superconductor, its superconductive order-parameter Δ_k has not yet been established. If spin-triplet, it should have odd parity so that Δ_(-k)=-Δ_k and, in addition, may break time-reversal symmetry. A distinctive identifier of 3D spin-triplet topological superconductors is the appearance of an Andreev bound state (ABS) on all surfaces parallel to a nodal axis, due to the presence of a topological surface band (TSB). Moreover, theory shows that specific ABS characteristics observable in tunneling to an s-wave superconductor distinguish between chiral and non-chiral Δ_k. To search for such phenomena in UTe2 we employ s-wave superconductive scan-tip imaging of UTe2 [1] to discover a powerful zero-energy ABS signature at the (0-11) crystal termination [2]. Its imaging yields quasiparticle scattering interference signatures of two Δ_k nodes aligned with the crystal a-axis. Most critically, development of the zero-energy Andreev conductance peak into two finite-energy particle-hole symmetric conductance maxima as the tunnel barrier is reduced, signifies that UTe2 superconductivity is non-chiral. Overall, the discovery of a TSB, of its a zero-energy ABS, of internodal scattering along the a-axis, and of splitting the zero-energy Andreev conductance maximum due to s-wave proximity, categorizes the superconductive Δ_k as the odd-parity non-chiral B3u state [2], which is equivalent to the planar state of superfluid 3He.
[1] Nature 618, 921 (2023)
[3] Gu, Wang, et al. Science (2023) | |
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07 Mar 2024
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 14:00 Uhr s.t., 01 122 Newton-Raum |
| Prof. Russell Cowburn, University of Cambridge Cambridge United Kingdom | |
An amazing range of new magnetic nanomaterials have been developed by the semiconductor and data storage industry as part of their adoption of spintronic technologies. Most of these materials are focused on the storage, retrieval and processing of digital data, e.g. hard disk drives in the Cloud or new designs of low energy microprocessors. But could these same materials be used for other things, outside of the world of digital data? In this talk I describe how we have re-tasked advanced magnetic nanomaterials for problems in biomedicine. In particular, I show a novel form of cancer therapy based on mechanical disruption of cellular structure using spinning magnetic nanostructures, our work towards early stage detection of kidney cancer using magnetic nanostructures and work on live adherent cells riding on the backs of nanostructured magnetic carriers for drug discovery. | |
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20 Mar 2024
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Tom Tong, Siegen U. | |
The SMEFT global analyses commonly encounter two significant challenges:
1. An incomplete set of observables.
2. Ad-hoc flavor assumptions.
These issues significantly undermine the reliability and applicability of the results.
In our recent work, we merged LHC data with EWPO and revealed that global fits to this data set exhibit striking discrepancies with low-energy data. Our findings underscore the necessity of including low-energy observables, such as neutron and nuclear beta decay, along with meson decays, in SMEFT global fits.
By integrating insights from collider processes (C), low-energy processes (L), and electroweak precision observables (EW), we introduce a holistic CLEW approach, and as a case study, we shed light on potential BSM sources of the Cabibbo Angle Anomaly (CAA), which demonstrates roughly a 3-sigma deviation. We were able to apply strong phenomenological constraints instead of relying on flavor assumptions to reduce the number of operators involved, facilitating a nearly flavor-assumption-independent global analysis.
Moreover, to aid in model building and guide experimental searches, we utilized the Akaike Information Criterion (AIC) to identify the most relevant operators. The AIC helps select a group of operators that not only fit well with the experimental data but also avoid unnecessary complexity.
Additionally, I aim to further discuss the importance of including low-energy neutral current data. The remarkable precision of the P2 experiment at MESA will be competitive with existing collider measurements. We are currently upgrading our CLEW framework to fully incorporate low-energy parity violation, including the future projection of P2. | |
Special Seminar with KPH |
16 Apr 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Ulrich Stroth, Max Planck Institute for Plasma Physics, Garching | |
In times of a shift towards a low CO2 energy supply and boosted by the recent success of laser fusion, the advantages of nuclear fusion in general have come into the focus of politics and private investors as an attractive energy source. This talk introduces the concept of magnetic fusion and outlines the path to a fusion reactor. The perspectives of magnetic fusion will be compared with those of laser fusion and the concepts of startups. The role of plasmas, in which energy is obtained from the fusion of hydrogen isotopes, and their physical properties are explained. Slides here... | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Julio Virrueta, Jena U. | |
I will discuss the real-time dynamics of metric perturbations around the AdS black hole and argue that the dynamic of these modes is captured by a set of designer scalars in the background geometry. Using these results I will obtain the real-time Gaussian effective action, which includes both the retarded response and the associated stochastic fluctuations. Finally, I will discuss extensions beyond linear response. | |
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17 Apr 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Koichi Hamaguchi, Univ./IPMU Tokyo, Japan | |
Supernova-Scope for the Direct Search of Supernova Axions | |
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18 Apr 2024
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
F. Schmid / G. Settanni / P. Virnau / L. Stelzl 14:30 Uhr s.t., Minkowski-Raum, 05-119, Staudingerweg 7 |
| Felix Höfling, Freie Universität Berlin | |
Emergent phenomena in flowing matter | |
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Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Dr. Felix Tennie, Imperial College, London, UK | |
Nonlinear differential equations are ubiquitous in Physics, Engineering, Chemistry, Materials Science, and various other subjects. Numerical integration often requires resources exceeding current classical supercomputers. Quantum computing presents a fundamentally different computing paradigm. Quantum algorithms have a proven scaling advantage in many linear tasks such as Fourier transformation, matrix inversion, SVD, to name but a few. Yet, due to the linear evolution of quantum systems, integrating nonlinear dynamics on quantum computers is hard. In this talk I will present different approaches for integrating nonlinear differential equations on quantum computers, and will discuss their suitability for different types of quantum hardware. | |
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22 Apr 2024
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Annika Stein, Institut für Physik | |
Novel Jet Flavour Tagging Algorithms exploiting Adversarial Deep Learning Techniques | |
| at https://indico.him.uni-mainz.de/event/199/ | |
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RHIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16:00 Uhr s.t., None |
| Giovanni Felder, ETH-Zürich | |
Towards a mathematical description of superstring perturbation theory | |
| at Zoom, BigBlueButton | |
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23 Apr 2024
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Yann Gouttenoire, Tel Aviv U. | |
Cosmological first-order phase transitions are said to be strongly supercooled when the nucleation temperature is much smaller than the critical temperature. The phase transition takes place slowly and the probability distribution of bubble nucleation times is maximally spread. Hubble patches which get percolated later than the average are hotter than the background after reheating and potentially collapse into primordial black holes (PBHs). I will give a review of this PBHs formation mechanism and of its most recent developments. | |
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24 Apr 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Bastian Märkisch, TU München | |
Neutron Beta Decay with Perkeo III and Perc | |
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25 Apr 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Prof. Dr. Ralf Röhlsberger, DESY, Hamburg | |
Using the high-intensity radiation of the European X-ray Free-Electron Laser, we recently succeeded to excite the sharpest atomic transition in the hard X-ray range, the 12.4 keV nuclear resonance of the stable isotope Scandium-45 [1].
With its extremely narrow natural linewidth of 1.4 femto-eV, it opens not only new possibilities for the development of a nuclear clock, but also for research linked to the foundations of physics, such as time variations of the fundamental constants, the search for dark matter as well as probing the foundations of relativity theory.
Furthermore, our experiment demonstrates the great potential of self-seeding X-ray lasers with high pulse rates as a promising platform for the spectroscopy of extremely narrow-band nuclear resonances.
The next steps towards a nuclear clock based on Scandium-45 require a further increase of the spectral photon flux using improved X-ray laser sources at 12.4 keV and the development of frequency combs reaching up to this energy.
[1] Yuri Shvyd’ko et al., Nature 622, 471 (2023) | |
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26 Apr 2024
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 12:00 Uhr s.t., Media Room |
| Kilian Leutner and Thomas Winkler, JGU Mainz | |
This Friday, the 26th, from 12 to 2 pm, Kilian Leutner and Thomas Winkler will give a test run of the "Intermag 2024 Hands-on session: AI in magnetism."
We will give an introductory talk (~30 minutes) about AI in magnetism and more concrete information about our recent project: "AI-accelerated detection of spin structures in Kerr-microscopy data."
Afterward, we will ask you to open your laptops and participate actively in the AI revolution. We will guide you through our repository. The goal is that participants can infer data and even train models on their own at the end of the session.
If you are interested, feel free to have a look at our paper and official repository:
Paper: Labrie-Boulay et al., Phys. Rev. Appl. 21, 014014 (2024): https://doi.org/10.1103/PhysRevApplied.21.014014
Repository (v2.0): Winkler et al., Zenodo repository: https://doi.org/10.5281/zenodo.10997175
If you would like to join, please send an email to Kilian Leutner ( kileutne@students.uni-mainz.de ) by Thursday. Kilian Leutner will eventually send around links for a smaller data repository, install instructions this week for the session.
You can participate in this session at the Physics building in Mainz in the “Medienraum” (03-431), or you can access the session via Teams using the following link: https://teams.microsoft.com/l/meetup-join/19%3ameeting_MTRhNjI4ZWYtNDkyMC00YzQ1LWIyNzgtMzkxNjAzYjNjYjY2%40thread.v2/0?context=%7b%22Tid%22%3a%2251aa2b30-c9fa-40db-b91a-3a53a8a08d85%22%2c%22Oid%22%3a%22e50b859d-212d-4ce0-b8ca-82e26bd02e43%22%7d .
(As this is a test talk, we are also happy about some feedback) | |
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Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 12:00 Uhr s.t., Media Room |
| Kilian Leutner and Thomas Winkler, JGU Mainz | |
This Friday, the 26th, from 12 to 2 pm, Kilian Leutner and Thomas Winkler will give a test run of the "Intermag 2024 Hands-on session: AI in magnetism."
We will give an introductory talk (~30 minutes) about AI in magnetism and more concrete information about our recent project: "AI-accelerated detection of spin structures in Kerr-microscopy data."
Afterward, we will ask you to open your laptops and participate actively in the AI revolution. We will guide you through our repository. The goal is that participants can infer data and even train models on their own at the end of the session.
If you are interested, feel free to have a look at our paper and official repository:
Paper: Labrie-Boulay et al., Phys. Rev. Appl. 21, 014014 (2024): https://doi.org/10.1103/PhysRevApplied.21.014014
Repository (v2.0): Winkler et al., Zenodo repository: https://doi.org/10.5281/zenodo.10997175
If you would like to join, please send an email to Kilian Leutner ( kileutne@students.uni-mainz.de ) by Thursday. Kilian Leutner will eventually send around links for a smaller data repository, install instructions this week for the session.
You can participate in this session at the Physics building in Mainz in the “Medienraum” (03-431), or you can access the session via Teams using the following link: https://teams.microsoft.com/l/meetup-join/19%3ameeting_MTRhNjI4ZWYtNDkyMC00YzQ1LWIyNzgtMzkxNjAzYjNjYjY2%40thread.v2/0?context=%7b%22Tid%22%3a%2251aa2b30-c9fa-40db-b91a-3a53a8a08d85%22%2c%22Oid%22%3a%22e50b859d-212d-4ce0-b8ca-82e26bd02e43%22%7d .
(As this is a test talk, we are also happy about some feedback) | |
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29 Apr 2024
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Jan Weldert, Pennsylvania State University | |
Atmospheric neutrino oscillations with the IceCube Upgrade | |
| at https://indico.him.uni-mainz.de/event/199/ | |
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30 Apr 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Joacim Rocklöv, Heidelberg University | |
In this talk I will introduce infectious diseases and their sensitivity to climate variability and change. I will describe and contrast experimental evidence with empirical observations and data. In the talk I will discuss systems and interactions enabling introduction and transmission of emergent vectors, hosts, and pathogens. I will further give examples of how mathematical process-based models and machine learning approaches are used and how they can be applied to study patterns and responses to these changes. Finally, I will talk about novel applications of machine learning in surveillance and early warnings, as well as the evaluation of interventions to guide effective responses. Slides here... | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Marco Fedele, IFIC, Valencia | |
In the last decade, several measurements have been hinting at the possibility of Beyond Standard Model physics in B decays. Some of these observables have stayed “anomalous” after several experiments released multiple measurements of such quantities, while others have recently suffered a different fate. In this seminar I will recap the current status of experimental anomalies, critically reviewing the theoretical description of these observables in the Standard Model. I will therefore identify which are the quantities with the highest probability of being affected by New Physics, and which are the ones that on the other hand do not require an extension of the SM any longer. | |
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02 May 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Dr. Matthias Christandl, University of Copenhagen, Denmark | |
In these days, we are witnessing amazing progress in both the variety and quality of platforms for quantum computation and quantum communication. Since algorithms and communication protocols designed for traditional 'classical' hardware do not employ the superposition principle and thus provide no gain even when used on quantum hardware, we are in need of developing specific quantum algorithms and quantum communication protocols that make clever use of the superposition principle and extract a quantum advantage. "Quantum hardware needs quantum software", so to say. Furthermore, due to noise in the qubits, known as decoherence, an additional quantum-specific software layer is required that emulates a perfect quantum machine on top of a noise one. I will demonstrate our recent work on this subject with theorems as well data from university and commercial quantum devices. | |
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07 May 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Michael Kramer, Max Planck Institute for Radio Astronomy, Bonn | |
Pulsars, the natural beacons of the universe, put physics to extreme test. As neutron stars, they are not only the densest objects in the observable universe, but they also serve as high-precision laboratories for testing the general theory of relativity. Pulsars not only allow the observation of predicted effects that cannot be observed by other methods, but they provide also extremely precise tests of the properties of gravitational waves. The latest results even use pulsars as galactic gravitational wave detectors, which detect a continuous "hum" of space-time. This buzz is, most likely, caused by the merging of supermassive black holes in the early universe. The talk gives an overview of the latest results and an outlook into the future. Slides here... | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Antonela Matijašić, MPP, Munich | |
The state-of-the-art in current two-loop QCD amplitude calculations is at five-particle scattering. In contrast, very little is known at present about two-loop six-particle scattering processes. In recent years, the results for one-loop hexagon integrals to higher order in the dimensional regulator become available as well as the results on the maximal cut of the planar two-loop six-point integral families. In this talk, I will show the progress made in computing planar two-loop six-particle Feynman integrals beyond the maximal cut using the differential equations method. In particular, I will discuss the canonical basis for several integral families in four space-time dimensions and their function space. | |
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08 May 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Gregor Kasieczka, Universität Hamburg | |
Modern machine learning and artificial intelligence are starting to fundamentally change how we analyse huge volumes of data in particle physics and adjacent scientific disciplines. These breakthroughs promise new insights into major scientific questions such as the nature of dark matter or the existence of physical phenomena beyond the standard model.
This colloquium will provide an overview of recent, exciting developments with a focus on model agnostic discovery strategies — including first experimental results, fast simulations, and foundation models that simultaneously solve multiple tasks across multiple data sets.
Slides:
https://drive.google.com/file/d/1PR2orzm-tn63oeV3IUxe1xLrnWulskcz/view?usp=sharing | |
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13 May 2024
RHIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16:00 Uhr s.t., None |
| Alessandro Tanzini, SISSA Triest | |
Painlevé/gauge theory correspondence and topological strings | |
| at Zoom, BigBlueButton | |
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14 May 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Jochem Marotzke, Max Planck Institute for Meteorology, Hamburg | |
I will first illustrate two key conclusions from the latest report of the Intergovernmental Panel on Climate Change, IPCC, from 2021. The first states that “it is unequivocal that human influence has warmed the atmosphere, ocean and land”. The second states that “global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades.” I will then explain how these results built on the work of Klaus Hasselmann and Syukuro Manabe, respectively, who shared the Nobel Prize in physics in 2021. The second of the statements was made possible through remarkable research progress during the past decade, and I will demonstrate how the scientific process within the IPCC turned a seeming scientific crisis into substantial progress. Finally, I will look at the still unsolved problem of understanding the future of the Atlantic Ocean circulation and how we tackle this problem in current research. Slides here... | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| João Penedo, INFN, Rome3 | |
In recent years, modular invariance has been applied to the SM flavour puzzle, yielding compelling results. In this string-inspired paradigm, one does not require a multitude of scalar fields (flavons) with aligned VEVs and complicated potentials. Taking a bottom-up approach, one may instead rely on a single complex field -- the modulus. Yukawa couplings and mass matrices are obtained from functions of its VEV, which can be the only source of flavour symmetry breaking and of CP violation. Such predictive modular setups may, among other things, shed light on the patterns of fermion mixing, the origin of fermion mass hierarchies and the strong CP problem. | |
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15 May 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. John Bulava, Universität Bochum | |
Although experimentally well-established, the nature of the Lambda(1405) hyperon resonance has long been a mystery. Constituent quark models have difficulty accommodating its low mass, while approaches based on chiral effective theory typically predict an additional state, the Lambda(1380), which is broad and difficult to identify. I will present the first lattice QCD computation of the coupled-channel $\pi\Sigma-\bar{K}N$ scattering amplitude in the Lambda(1405) channel, which employs quark masses so that the $\pi\Sigma$ threshold is approximately 1380 MeV. This enables the unambiguous identification of the Lambda(1380) in addition to the Lambda(1405), thus supporting the exotic meson-baryon `molecule' interpretation. Slides here... | |
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16 May 2024
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
F. Schmid / G. Settanni / P. Virnau / L. Stelzl 14:30 Uhr s.t., Minkowski-Raum, 05-119, Staudingerweg 7 |
| Sonya Hansen, Flatiron Institute | |
TBA | |
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Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Kenneth R. Brown, Duke University, USA | |
Conical intersections often control the reaction products of photochemical processes and occur when two electronic potential energy surfaces intersect. Theory predicts that the conical intersection will result in a geometric phase for a wavepacket on the ground potential energy surface, and although conical intersections have been observed experimentally, the geometric phase has not been directly observed in a molecular system. Here we use a trapped atomic ion system to perform a quantum simulation of a conical intersection. The ion’s internal state serves as the electronic state, and the motion of the atomic nuclei is encoded into the motion of the ions. The simulated electronic potential is constructed by applying state-dependent optical forces to the ion. We experimentally observe a clear manifestation of the geometric phase using adiabatic state preparation followed by motional state measurement. Our experiment shows the advantage of combining spin and motion degrees for quantum simulation of chemical reactions. We conclude with a discussion of future simulation directions. | |
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21 May 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Cristian Micheletti, SISSA, Trieste, Italy | |
Sampling equilibrium ensembles of dense polymer mixtures is a paradigmatically hard problem in computational physics, even in lattice-based models. For instance, using real-space Monte Carlo to sample polymer systems becomes impractical for increasing size, rigidity, and density of the chains. In response to these challenges, we introduce and apply a formalism to recast polymer sampling as a quadratic unconstrained binary optimization (QUBO) problem [1].
Thanks to this mapping, dense systems of stiff polymers on a lattice can be efficiently sampled with classical QUBO solvers, resulting in more favourable performance scaling compared to real-space Monte Carlo [2]. Tackling the same problems with the D-Wave quantum annealer leads to further performance improvements [2]. As an application, we discuss the use of the quantum-inspired encoding on a hitherto untackled problem, namely the linking probability of equilibrated melts of ring polymers, for which we unveil counterintuitive topological effects.
References
[1] C.Micheletti, P. Hauke and P. Faccioli, "Polymer physics by quantum computing", Phys. Rev. Lett. 127, 080501 (2021)
[2] F. Slongo, P. Hauke, P. Faccioli and C. Micheletti "Quantum-inspired encoding enhances stochastic sampling of soft matter systems", Sci. Adv. 9, art. no adi0204 (2023) Slides here... | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Guilherme Guedes, DESY | |
In this talk, I will go over the role of small instantons (SI) in increasing the axion mass. These SI will also enhance the effect of CP-violating operators which shift the axion potential minimum by an amount proportional to the flavorful couplings of the theory. Since physical observables must be flavor basis independent, we construct a basis of determinant-like flavor invariants that arise in instanton calculations containing the effects of dimension-six CP-odd operators. This new basis provides a more reliable estimate of the shift of the minimum of the axion potential, which is severely constrained by neutron electric dipole moment experiments. We show explicitly how these quantities arise in the case of 4-quark and semi-leptonic operators, and how they can be used to constrain the ratio of the scales of SI and CP-violation. More generally, the flavor invariants introduced, together with an instanton NDA, can be used to more accurately estimate small instanton effects in the axion potential arising from any effective operator. We will also discuss how other shift-breaking effects can be enhanced in the presence of SI. | |
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22 May 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Prateek Agrawal, Oxford, UK | |
Beyond the Standard Model through the Axion Lens | |
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23 May 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Dr. Hans Keßler, Universität Hamburg | |
In driven non-linear systems, various kinds of bifurcations can be observed on their route to chaos. From the evolution of Floquet multipliers one can extract information which serves as a precursor for phase transitions and dynamical instabilities. This method is applied in classical non-linear physics, for example, to obtain early warning signals.
Utilising our impressive control over an atom-cavity platform, we are able to prepare our system in various dynamical regimes and study the bifurcation experimentally in a quantum gas to obtain insights that could potentially be applied to more complex systems.
We prepare a Bose-Einstein condensate inside the centre of a cavity and pumping it perpendicular to the cavity axis with a standing wave light field. Upon crossing a critical pump strength, we observe a pitchfork phase transition from a normal to a steady state self-organized phase [1]. Employing an open three- level Dicke model, this transition can be understood as a transition between two fixpoints, indicating a pitchfork bifurcation. If the pump strength is increased further, the system undergoes a Hopf bifurcation. This causes limit cycles, which have time crystalline properties, to emerge [2]. In this regime, our model no longer shows fixpoints but stable attractive periodic orbits [3]. For strong pumping, we observe a second bifurcation, in our case a Neimark-Sacker bifurcation. Its main characteristics is an oscillation with two incommensurate frequencies, this may indicate the formation of a continuous time quasicrystal [4]. Finally, in the regime of very strong pumping, we observe chaotic dynamics with many contributing frequencies.
References:
[1] J. Klinder, et al., PNAS 112, 11 (2015)
[2] P. Kongkhambut, et al., Science 307 (2022)
[3] J. Skulte, et al., arXiv:2401.05332 (2023)
[4] P. Kongkhambut, et al., manuscript in preparation | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Anastasios Sourpis, JGU, Physics | |
Electrochemistry is a discipline promising to advance material science towards more environmentally friendly and sustainable technologies for energy solutions. Electrochemical systems are usually composed of interacting complex molecules, making understanding collective effects limited for macroscopic experiments. Computer simulations offer a way to obtain insights in silico. In particular, molecular dynamics simulations, with detailed interatomic potentials, allow us to rationalize experimental results by exploring the dynamics of physical systems through virtual experiments. In the first part of this thesis, I systematically review molecular dynamics simulation methods providing the foundation for preparing our physical system in silico. I introduce the basic principles of an all-atom molecular simulation within the framework of statistical physics and discuss in detail the treatment of electrostatic interactions and the importance of dielectric boundary conditions. In the second part of this thesis, I present our molecular dynamics study of a liquid system composed of water and acetonitrile molecules and their response to an external electric field. This mixture exhibits unique properties, including a distinctive electrical conductivity detection in the absence of an electrolyte in novel electrolysis flow cells. However, the underlying physical mechanism behind this phenomenon remains unknown. As a first step to understanding this mechanism, this work focuses on the bulk system structure and how a macroscopic external electric field influences its properties. | |
| at Zoom | |
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28 May 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Ingo Rehberg, University of Bayreuth | |
Spherical magnets are an invaluable but affordable physics toy! While vividly demonstrating chemical, physical and mathematical problems, they can also greatly inspire creativity: Questions concerning the favoured state of dipole cluster configurations lead – via an encounter with tipping points – to the invention of magnetic gears based on degenerate continua. Open source animations and patent-free hardware to play with shall garnish this triptychon. Slides here... | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Daniel Spitz, MPI Leipzig | |
Finding interpretable order parameters for the detection of topological dynamics and critical phenomena can be a challenging endeavour in lattice field theories. Tailored to detect and quantify topological structures in noisy data, topological data analysis (TDA) allows for the construction of sensitive observables. In this talk I will discuss two research projects, which highlight the potential of TDA for lattice field-theoretical studies. The first utilizes TDA to investigate the role of topological defects in regimes governed by universal self-similar dynamics. More specifically, in simulations of the paradigmatic O(N) vector model, the dynamics of topological defects can be studied via Betti curves computed from local energy densities. Based on Monte Carlo simulations of SU(2) lattice gauge theory, the second project shows how TDA computed from chromoelectric and -magnetic fields, topological densities and Polyakov loops can be used to uncover a multifaceted picture of the deconfinement phase transition.
This application-oriented talk is based on joint work with Viktoria Noel, Jan Pawlowski and Julian Urban. | |
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29 May 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Kathrin Valerius, KIT | |
Unfortunately, this talk had to be canceled due to unforeseen circumstances. | |
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03 Jun 2024
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 12:30 Uhr s.t., Gernot Gräff Room |
| X. R. Wang, 1The Hong Kong University of Science and Technology, China 2Chinese University of Hong Kong (Shenzhen), China | |
In this talk, I will first discuss several progresses made in our group about fundamental properties of skyrmions in chiral magnetic films. These include 1) skyrmion sizes in isolated, in crystal, or in stripy forms; 2) skyrmion nucleation, formation, and potential barrier energies; 3) the roles of magnetic field in skyrmion crystal formation; 4) the stability and existing conditions of composite skyrmions such as target skyrmions and skyrmion bags/cluster; 5) topological equivalence of stripy phases and skyrmion crystals. Then I will discuss a new theory about widely observed unusual anisotropic magnetoresistance (UAMR) in bilayers which leads to the notion of the spin-Hall MR (SMR) in the famous SMR theory. The theory is based on the universal features in all bilayer heterostructure: resistivity tensor depends on magnetization and interfacial field. I will show that the angular dependencies of UAMR do not depend on the microscopic details, thus are universal. Experiments that can test this theory against the SMR theory are also proposed.
** This work is supported by the National Key Research and Development Program (No. 2020YFA0309600), the NSFC Grant (No. 11974296), and HK RGC Grants (No. 16300523, 16300522, and 16302321). | |
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04 Jun 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Claudia Felser, Max Planck Institute for Chemical Physics of Solids, Dresden | |
Topology, a well-established concept in mathematics, has nowadays become essential to describe condensed matter. At its core are chiral electron states on the bulk, surfaces and edges of the condensed matter systems, in which spin and momentum of the electrons are locked parallel or anti-parallel to each other. Magnetic and non-magnetic Weyl semimetals, for example, exhibit chiral bulk states that have enabled the realization of predictions from high energy and astrophysics involving the chiral quantum number, such as the chiral anomaly, the mixed axial-gravitational anomaly and axions. The potential for connecting chirality as a quantum number to other chiral phenomena across different areas of science, including the asymmetry of matter and antimatter and the homochirality of life, brings topological materials to the fore. Slides here... | |
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05 Jun 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Jacobo López-Pavón, Universidad de Valencia, Spain | |
Recent Developments in Heavy Neutral Leptons | |
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06 Jun 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Nicolò Defenu, ETH Zürich | |
The concept of universality has shaped our understanding of many-body physics, but is mostly limited to homogenous systems. The seminar introduces a definition of universal scaling on a non-homogeneous graph. The corresponding scaling theory is expected to depend only on a single parameter, the spectral dimension ds, which plays the role of the relevant parameter on complex geometries. We will then focus on a concrete example, the long-range diluted graph (LRDG), which allows to tune the value of the spectral dimension continuously. By means of extensive numerical simulations, we probe the scaling exponents of a simple instance of O(N) symmetric models on the LRDG showing quantitative agreement with the theoretical prediction of universal scaling in fractional dimensions. | |
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11 Jun 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Dr. Karen Alim, TU München | |
Propagating, storing and processing information is key to take smart decisions – for organisms as well as for autonomous devices. In search for the minimal units that allow for complex behaviour, the slime mould Physarum polycephalum stands out by solving complex optimization problems despite its simple make-up. Physarum’s body is an interlaced network of fluid-filled tubes lacking any nervous system, in fact being a single gigantic cell. Yet, Physarum finds the shortest path through a maze. We unravel that Physarum’s complex behaviour emerges from the physics of active flows shuffling through its tubular networks. Flows transport information, information that is stored in the architecture of the network. Thus, tubular adaptation drives processing of information into complex behaviour. Taking inspiration from the mechanisms in Physarum we outline how to embed complex behaviour in active microfluidic devices and how to program human vasculature. Slides here... | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Melissa van Beekveld, Nikhef | |
Parton showers are essential tools for interpreting particle-collision data. To get the most out of available and upcoming data, it is important that these showers incorporate state-of-the-art theoretical predictions. The PanScales project aims to design parton showers that achieve higher logarithmic accuracy than any of the standard tools used at present. This talk will discuss the construction of logarithmically accurate parton showers, including the recent achievement of next-to-next-to-leading-logarithmic accuracy for the wide class of e+e- observables known as event shapes, and its impact on phenomenology. | |
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12 Jun 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Jessica Turner, IPPP, Durham University, UK | |
I will discuss how proton decay, combined with gravitational waves, can be used to test Grand Unified Theories (GUTs). In particular, proton decay searches by large multipurpose neutrino experiments such as DUNE, Hyper-Kamiokande, and JUNO will either discover proton decay or further push the symmetry-breaking scale above 10^16 GeV. Another possible observational consequence of GUTs is the formation of a cosmic string network produced during the breaking of the GUT to the Standard Model gauge group, which can produce a stochastic background of gravitational waves. Several gravitational wave detectors will be sensitive to this over a wide frequency range. I will demonstrate the non-trivial complementarity between the observation of proton decay and gravitational waves produced from cosmic strings in determining SO(10) GUT breaking chains and their compatibility with leptogenesis as a means of producing the observed matter-antimatter asymmetry. Additionally, I will extend this discussion to include supersymmetric GUTs, taking into account recent findings from Pulsar Timing Arrays that have detected gravitational waves in the nanoHertz frequency range. Slides here... | |
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Seminar über Theorie der kondensierten Materie / TRR146 Seminar
F. Schmid / G. Settanni / P. Virnau / L. Stelzl 15:30 Uhr s.t., Lorentz-Raum, 05-119, Staudingerweg 7 |
| Apratim Chatterji, Prof | |
Under high cylindrical confinement, segments of ring polymers with internal loops can be made to
get localized along the long axis of the cylinder. The emergent organization of the polymer
segments occurs because of the entropic repulsion between internal loops which mutually exclude
each other position along the long axis of the cylinder [Phys.Rev.E, 106, 054502 (2022)].
We used these localization properties of segments in such topologically modified bead-spring
models of ring polymers to identify the underlying mechanism of the evolution of bacterial
chromosome organization as the cell goes through its life cycle [Soft Matter 18, 5615-5631 (2022)].
Here, we show how to modify ring polymer topology by creating internal loops of two different
sizes within the polymer, and thereby create an asymmetry in the two halves of the modified ring-
polymer. This allows us to strategically manipulate and harness entropic interactions between
adjacent polymers confined in a cylinder, such that a polymer prefers to orient itself in a specific
way with respect to its neighbours. Thus, we can induce entropy driven effective interactions
reminiscent of Ising-spin like interactions between adjacent topologically modified polymers. We
consider a completely flexible bead-spring model of polymers with only excluded volume
interactions between the monomers.
We extend the work to investigate the entropic organization of topologically modified ring-
polymers confined within a sphere. We observe that for a single topologically modified polymer
within a sphere, the monomers of the bigger loop are statistically probable to be found closer to the
periphery. However, the situation is reversed when we have multiple such topologically modified
polymers in a sphere. The monomers of the small loops are found closer to the walls of the sphere.
We can increase this effect by introducing a large number of small loops in each ring polymers. | |
|
13 Jun 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Prof. Eugene Polzik, University of Copenhagen, Denmark | |
Studies of extreme cases within quantum mechanics have always been particularly attractive. How macroscopic can objects be and still demonstrate unique quantum features, such as entanglement? What are the real limits of measurement precision in quantum mechanics? I will review our experiments where macroscopic objects are driven deep into the quantum regime. Observation of a quantum trajectory of motion in a quantum reference frame with, in principle, unlimited accuracy will be presented. A concept of a reference frame with an effective negative mass required for such observation will be introduced. Generation of an entangled Einstein-Podolsky-Rosen state between distant mechanical and atomic oscillators and progress towards application of those ideas to gravitational wave detection will be reported. Finally, a recent demonstration of entanglement enhanced magnetic induction tomography for medical applications will be presented. | |
|
17 Jun 2024
RHIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16:00 Uhr s.t., None |
| John Baez, UC Riverside | |
The Tenfold Way | |
| at Zoom, BigBlueButton | |
|
18 Jun 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Dr. Thomas Cocolios, KU Leuven, Belgium | |
Nuclear medicine is currently experiencing some major changes and developments: Lu-177 has become a standard radionuclide for patient care, in particular with Lutathera® and Pluvito®, two recently marketed drug for endocrine and prostate cancers, respectively. Those successes are but the tip of the iceberg of possibilities: with 3000 radionuclides synthesized in the laboratory, it seems unbelievable that only a handful are actually used in medical applications. This is mostly due to the absence of a supply pipeline to support research until their production is picked up by the industry. To break that paradigm, CERN has established the MEDICIS facility (MEDical Isotopes Collected from ISolde), where the techniques developed for the last 50 years on radioactive ion beams are now applied to produce medical radionuclides for research. The success of the development of non-carrier-added Sm-153 has led it to first clinical trials in 2024. At the European level, this has triggered a new consortium, federated around MEDICIS but with a larger reach, as PRISMAP, the European medical radionuclide programme. Slides here... | |
|
19 Jun 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Joel Swallow, CERN, Switzerland | |
The NA62 experiment at CERN is the worlds leading K+ laboratory, with the primary goal of studying the ultra-rare decay K+ --> pi+ nu nu. In the last few years several key upgrades have been implemented giving improved performance for our currently ongoing data-taking campaign.
In this colloquium I will introduce the NA62 experiment and this golden decay mode, K+ --> pi+ nu nu, and the latest news on the analysis status. NA62 has a broad physics programme and I will also present the latest results from across our research programme, including hot-off-the-press rare and forbidden K+ decay searches. Slides here... | |
|
20 Jun 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Dr. Janis Nötzel, TUM, München | |
In this talk, we address the question of how some theoretically predicted quantum advantages could be utilized in future system design. We start with an overview of various theoretical descriptions of quantum communication systems, focusing mainly on data transmission tasks involving topics such as Holevo capacity and entanglement-assisted capacity of a quantum channel as well as the use of entanglement for coordination in multiple access scenarios. We give a brief overview of the state of the art of implementations before moving on to an applied perspective, where we start from the state of the art in today's network design and explore the potential role of the above-mentioned quantum system descriptions for future networks.
We conclude the talk by formulating system design questions. | |
|
24 Jun 2024
RHIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16:00 Uhr s.t., None |
| Matthew Young, Utah State University | |
Abelian gauged Rozansky-Witten theory via quantum Lie superalgebras | |
| at Zoom, BigBlueButton | |
|
25 Jun 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Klaus Blaum, Max-Planck Institute for Nuclear Physics, Heidelberg | |
The four fundamental interactions and their symmetries, the fundamental constants as well as the properties of elementary particles like masses and moments, determine the basic structure of the universe and are the basis for our so well tested Standard Model (SM) of physics. Performing stringent tests on these interactions and symmetries in extreme conditions at lowest energies and with highest precision by comparing, e.g., the properties of particles and their counterpart, the antiparticles, will allow us to search for physics beyond the SM. Any improvement of these tests beyond their present limits requires novel experimental techniques.
An overview is given on recent mass and g-factor measurements with extreme precision on single or few cooled ions stored in Penning traps. Among others the most stringent test of bound-state quantum electrodynamics could be performed. Here, the development of a novel technique, based upon the coupling of two ions as an ion crystal, enabled the most precise determination of a g-factor difference to date. This difference, determined for the isotopes 20,22Ne9+ with a relative precision of 5 × 10−13, improved the precision for isotopic shifts of g factors by about two orders of magnitude. Our latest results on precision measurements with exotic ions in Penning traps will be presented. Slides here... | |
|
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Lisong Chen, KIT | |
Future electron-positron colliders, such as the CEPC, FCCee, and ILC, are poised to explore a new precision frontier, enabling an unprecedented level of scrutiny of the electroweak (EW) sector of the Standard Model (SM) and potentially uncovering new physics beyond the SM. Achieving this requires a deeper understanding of the SM through the calculation of radiative corrections to various well-defined observables, specifically the electroweak precision observables (EWPOs).
The first part of the talk provides a brief review of the EWPOs and the forefront of precision studies of these observables at future electron-positron colliders. In the second part, we introduce a novel modular framework for describing EW scattering and decay processes, including but not limited to Z-resonance physics. This framework maintains gauge invariance while ensuring extensibility. It has been implemented in the publicly available object-oriented C++ library GRIFFIN, featuring full NNLO and leading higher-order contributions on the Z-resonance, as well as NLO corrections off resonance. This framework is also capable of making predictions for new physics models relevant to these processes and can interface with Monte Carlo programs to account for real radiation. | |
|
26 Jun 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Alessandro Lovato, Argonne National Lab, USA | |
Uncertainty Quantification in Nuclear Physics | |
|
RHIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16:00 Uhr s.t., None |
| Yizhen Zhao, Weizmann | |
Open 𝑟r-spin and FJRW theory via the point insertion technique | |
| at Zoom, BigBlueButton | |
|
27 Jun 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Prof. Oded Zilberberg, Universität Konstanz | |
Topological classification of matter has become crucial for understanding (meta-)materials, with associated quantized bulk responses and robust topological boundary effects [1]. Topological phenomena have also recently garnered significant interest in nonlinear systems [2]. In particular, weak nonlinearities can result in parametric gain, leading to “non-Hermitian” metamaterials and the associated topological classification of open systems [3]. Here, we venture into this expanding frontier using an approach that moves away from quasilinear approximations around the closed system classification. We harness instead the topology of structural stability of vector flows, and thus propose a new topological graph invariant to characterize nonlinear out-of-equilibrium dynamical systems via their equations of motion. We exemplify our approach on the ubiquitous model of a dissipative bosonic Kerr cavity, subject both to one- and two-photon drives. Using our classification, we can identify the topological origin of phase transitions in the system, as well as explain the robustness of a multicritical point in the phase diagram. We, furthermore, identify that the invariant distinguishes population inversion transitions in the system in similitude to a Z2 index. Our approach is readily extendable to coupled nonlinear cavities by considering a tensorial graph index.
References
[1] T. Ozawa, H. M. Price, A. Amo, N. Goldman, M. Hafezi, L. Lu, M. Rechtsman, D. Schuster, J. Simon, O. Zilberberg, and I. Carusotto, Rev. Mod. Phys. 91, 015006 (2019).
[2] A. Szameit, and M. C. Rechtsman, Nat. Phys. (2024).
[3] K. Ding, C. Fang, and G. Ma, Nat. Rev. Phys. 4, 745 (2022). | |
|
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 14:00 Uhr s.t., 01 122 Newton-Raum |
| Yaroslav Tserkovnyak, University of California, Los Angeles | |
I will review our recent work that aims at harvesting quantum fluctuations of magnetic systems, with both quantum information and many-body physics in mind. Focusing on magnons as building blocks of collective spin dynamics in magnetic insulators, I will discuss the prospects of their scalable integration with proximal color centers, such as nitrogen-vacancy impurities, using the latter as either quantum sensors, which can be operated in a range of different physical modalities, or qbits, whose entangled dynamics is governed by the common dissipative magnonic environment. Recent experiments on using color centers as spectrally-resolved sensors of magnetic dynamics demonstrate their strong coupling with a range of 2D materials. Inspired in part by the ideas from quantum optics, we are now pursuing the inverse functionality: imprinting collective noise of the tunable environment onto emergent many-body properties of color-center ensembles. | |
|
02 Jul 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Laura Kreidberg, Max Planck Institute for Astronomy, Heidelberg | |
The recent launch of the James Webb Space Telescope (JWST) has revolutionized the field of exoplanet atmosphere characterization, thanks to its unprecedented sensitivity and broad wavelength coverage. In this talk, I will give a tour of the latest JWST results for transiting exoplanets, from gas giants down to rocky worlds. For the largest planets, I'll focus on the complex physical processes recently revealed in their atmospheres, including photochemistry, 3D effects, and cloud formation. Pushing down to smaller worlds, I'll share the first measurements of chemical composition for the elusive sub-Neptune population; and finally give an update on which (if any) rocky planets have atmospheres at all. Slides here... | |
|
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Jorinde van de Vis, Leiden U. | |
In many extensions of the Standard Model, the universe underwent one or several first order phase transitions. Such phase transitions proceed via the formation and collision of bubbles. The bubble collisions can source a stochastic gravitational wave background signal. In the case of the electroweak phase transition, the characteristic frequency would fall right in the sensitivity band of LISA. We can thus use data from gravitational wave experiments to probe physics beyond the standard model. In this talk, I will discuss the contribution to the gravitational wave signal from sound waves, which is often the dominant contribution.
Predictions of the gravitational wave spectrum typically rely on hydrodynamic lattice simulations of the scalar-plasma system. Hydrodynamic solutions of a single expanding bubble provide a bridge between the particle physics model and the hydrodynamic lattice simulation and encode much of the underlying particle physics information. Two relevant quantities in this computation are the bubble expansion velocity and the kinetic energy budget. I will discuss the computation of both quantities and present two approximation schemes for computing the wall velocity: the scenario of local thermal equilibrium and of a large enthalpy jump between the two phases. | |
|
03 Jul 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| PD Dr. Teresa Marrodan, MPI Heidelberg | |
The nature of dark matter is one of the most important open questions in modern physics. Astronomical and cosmological measurements provide strong evidence for its existence. Despite the many hypothetical candidate particles that have been proposed, experimental efforts have so far yielded only null results. Direct detection is a promising method for determining the nature of this dark component of the Universe. It allows, for example, to probe the existence of WIMPs (Weakly Interacting Massive Particles) via their elastic scattering off target nuclei down to tiny interaction cross sections. Several experimental strategies have been developed to measure the small recoil induced by dark matter interactions, with liquid xenon TPCs being one of the most successful.
This talk will discuss the status and main results of XENONnT and outline future plans with the DARWIN/XLZD observatory. Slides here... | |
|
08 Jul 2024
RHIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16:00 Uhr s.t., None |
| Catherine Meusburger, University of Erlangen | |
Dijkgraaf-Witten TQFT with defects | |
| at Zoom, BigBlueButton | |
|
09 Jul 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| - canceled - Dr. Kerem Çamsarı, University of California, Santa Barbara | |
tba | |
|
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Peter Reimitz, Sao Paulo U. | |
High-luminosity colliders and fixed-target facilities using proton beams are sensitive to new weakly coupled degrees of freedom across a broad mass range. In this talk, we will discuss various production modes for dark vector particles in proton beam experiments. First, we will set the stage by reviewing light physics models, including new vector particles, discuss how these models could solve the shortcomings of the SM, and present some current and future search strategies. After briefly discussing dark photon production in meson decays and Drell-Yan, we will have a closer look at dark bremsstrahlung. Dark bremsstrahlung is particularly important for dark vectors with masses between 0.5-1.5 GeV due to resonant mixing with hadronic resonances. This production mode will be crucial for sensitivity predictions for future experiments like SHiP and proposals like the Forward Physics Facility. We revisit the calculation of dark photons via initial state radiation in non-single diffractive scattering, using an improved approach to the splitting function and the timelike electromagnetic form factor. | |
|
10 Jul 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Louis Strigari, Texas University, USA | |
Astrophysical and Terrestrial Applications of Coherent Neutrino Scattering | |
|
11 Jul 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Prof. Nir Bar-Gill, Hebrew University, Jerusalem | |
The study of open quantum systems, quantum thermodynamics and quantum many-body spin physics in realistic solid-state platforms, has been a long-standing goal in quantum and condensed-matter physics. In this talk I will address these topics through the platform of nitrogen-vacancy (NV) spins in diamond, in the context of bath characterization, purification (or cooling) of a spin bath as a quantum resource and for enhanced metrology and sensing.
I will first describe our work on characterizing noise using robust techniques for quantum control ([1], in collaboration with Ra’am Uzdin). This approach suppresses sensitivity to coherent errors while enabling noise characterization, providing a useful tool for the study of complicated open quantum systems, with the potential for contributions to enhanced sensing. I will then present a general theoretical framework we developed for Hamiltonian engineering in an interacting spin system [2]. This framework is applied to the coupling of the spin ensemble to a spin bath, including both coherent and dissipative dynamics [3]. Using these tools I will present a scheme for efficient purification of the spin bath, surpassing the current state-of-the-art and providing a path toward applications in quantum technologies, such as enhanced MRI sensing.
Finally, if time permits, I will describe our work in using NV-based magnetic microscopy to implement quantum sensing in various modalities. I will present advanced techniques for improving sensing bandwidth using compressed sensing and machine learning. Demonstrations of NV sensing capabilities will include measurements of 2D vdW magnetic materials, and specifically the phase transition of FGT through local imaging of magnetic domains in flakes of varying thicknesses [4], as well as a technique for sensing radical concentrations through the change in the charge state of shallow NVs ([5], in collaboration
with Uri Banin).
1. P. PENSHIN ET. AL., SUBMITTED.
2. K. I. O. BEN’ATTAR, D. FARFURNIK AND N. BAR-GILL, PHYS. REV. RESEARCH 2, 013061 (2020).
3. K. I. O. BEN’ATTAR ET. AL., IN PREPARATION.
4. G. HAIM ET. AL., IN PREPARATION.
5. Y. NINIO ET. AL., ACS PHOTONICS 8, 7, 1917-1921 (2021). | |
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Seminar über Theorie der kondensierten Materie / TRR146 Seminar
F. Schmid / G. Settanni / P. Virnau / L. Stelzl 16:15 Uhr s.t., Minkowski-Raum, 05-119, Staudingerweg 7 |
| Lisa Hartung, Prof | |
Interacting particle systems and partial differential equations | |
|
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 14:00 Uhr s.t., 01 122 Newton-Raum |
| Satoru Emori, Department of Physics, Virginia Polytechnic Institute and State University, U.S.A. | |
Energy-efficient spintronic devices require a large spin-orbit torque (SOT) and low damping to excite magnetic precession. In conventional devices based on heavy-metal/ferromagnet bilayers, reducing the ferromagnet thickness to ~1 nm enhances the torque – but dramatically increases the damping.
I will present my team’s new approach toward attaining low damping and a sizable SOT in single-layer, 10-nm-thick FeNi alloys. A vertical Fe:Ni compositional gradient is designed to provide the necessary asymmetry for SOT generation. We confirm low effective damping in FeNi even with a steep compositional gradient. More remarkably, we reveal a sizable anti-damping SOT even without any intentional compositional gradient. Through noninvasive depth-profile measurements, we identify a lattice strain gradient as the key asymmetry giving rise to the SOT. Our findings provide fresh insights into damping and SOTs in single-layer ferromagnets for power-efficient spintronic devices. | |
|
15 Jul 2024
RHIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16:00 Uhr s.t., None |
| Emanuel Scheidegger, Peking University | |
TBA | |
| at Zoom, BigBlueButton | |
|
16 Jul 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Frank Saueressig, Radboud University, NL | |
Fusing the principles of general relativity and quantum mechanics in a consistent theoretical framework still constitutes one of the main open challenges in theoretical physics today. Over the last decades, the gravitational asymptotic safety program has taken significant steps towards achieving this goal. A central virtue, driving the success of the approach, is its conservative nature: the program builds on well-established principles of quantum field theory and extends them in a rather minimalistic way. In this talk, we will review the key developments in the program, building up to its present status. I will also attempt to give an outlook on the challenges that need to still be addressed in the future. Slides here... | |
|
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Reinhard Noack, Philipps University Marburg | |
Correlated Electrons from Zero to Infinite Dimensions: Early Days of KOMET 7 in Mainz.
I will talk about the problems in correlated electron systems that occupied us in the early days of the KOMET 7 research group headed by Peter van Dongen. These problems include quantum impurity problems as well as the dynamical mean field theory (DMFT), i.e., correlated electrons in the infinite-dimensional limit. At first glance, these two problems are very different because the impurity problem is in a sense zero-dimensional, whereas the DMFT is formally infinite-dimensional. However, the effective problems and solution methods of these two problems are losely related, and both approaches can be used to describe the behavior of real three-dimensional materials. In addition, a major activity of group members has been to develop and use matrix-product-state and tensor-network methods, especially the density matrix renormalization group.
These methods are ideally suited to study quasi-one-dimensional and two-dimensional strongly correlated systems. They can be applied to a variety of
systems ranging from transition-metal coumpounds such as the cuprates to organometallic materials such as Bechgaard salts as well as to quantum simulators formed from cold atomic gases on optical lattices. Slides here... | |
|
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Jordy de Vries, Amsterdam U., Nikhef | |
The fact that neutrinos are massive particles can be neatly explained by the existence of (at least two) additional neutrinos, called sterile neutrinos. Depending on their mass, sterile neutrinos can be looked for in various experiments. I will discuss how sterile neutrinos can be probed indirectly in neutrinoless double beta decay experiments and how this search compares to more direct probes and how it can test low-scale leptogenesis as a solution for the baryon number asymmetry of the universe. | |
|
17 Jul 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Stefan Schoenert, TU Munich | |
Since neutrinos have no electric charges, they may be their own antiparticles, referred to as Majorana neutrinos, and thus violate lepton number conservation. Neutrinoless double beta decay would be a direct consequence, and the search for this decay mode is the most sensitive method to unravel the Majorana nature of neutrinos. By operating bare germanium diodes, enriched in Ge-76, in an active liquid argon shield, GERDA achieved an unprecedently low background index of 5.2∙10−4 counts/keV kg yr in the signal region and collected an exposure of 127 kg yr in a background-free regime. No signal was observed, and a limit on the half-life of 0νββ decay in Ge-76 is set at T1/2 > 1.8∙1026 yr (90 % C.L.) [1] and Majorana neutrino masses are constrained to mββ< 79–180meV (90\% C.L.). The LEGEND Collaboration builds on the success of GERDA and MJD, and develops a phased, Ge-76-based double-beta decay experimental program with a T1/2 - discovery potential beyond 1028 years. Its first stage, LEGEND-200, started data-taking in early 2023, and LEGEND-1000 is under preparation. The first results from LEGEND-200, based on 48.3 kg·yrs of data, were presented in June at the Neutrino 2024 conference in Milan and will be discussed. | |
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22 Jul 2024
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 16:00 Uhr s.t., 01 122 Newton-Raum |
| Elisa De Ranieri, Editor-in-Chief, Newton | |
Ever wondered how influential journals select content for publication and how peer review works? In this talk, I will discuss the editorial process at these journals, which typically rely on professional editors, focusing in particular on the Cell Press portoflio and introducing Newton, our new flagship physics journal. I will also share my views on current trends in scientific publishing, and provide tips on how to maximise the fit of your manuscript for high-impact journals and on how to deliver an appropriate reviewer report if you are invited to review a manuscript. | |
|
30 Jul 2024
Theorie-Palaver
Institut für Physik Sonderseminar: 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Andrew McLeod, Edinburgh U. | |
While the mathematical structure of scattering amplitudes has long been known to be constrained by principles such as causality and locality, the explicit form of these constraints has remained difficult to work out in practice. In this talk, I present a new method that sidesteps many of these difficulties, which allows us to derive large classes of novel constraints on Feynman integrals. In particular, through the identification of what singularities can still be reached after localizing to certain minimal cuts, strong restrictions can be placed on the ordered pairs of discontinuities that are allowed to appear in Feynman integrals. These restrictions, which we refer to as genealogical constraints, can be worked out for integrals involving arbitrary configurations of massive and massless particles, and hold to all orders in dimensional regularization. | |
Sonderseminar | |
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15 Aug 2024
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 14:00 Uhr s.t., 01 122 Newton-Raum |
| Prof. Shixun Cao, Institute for Quantum Science and Technology Shanghai University | |
This presentation is to introduce our published science paper (Science 361, 794–797 (2018)), which is a cooperation work of Shanghai University and Rice University, Osaka University, Japan Science and Technology Agency, Argonne National Laboratories, Peking University, Universität Duisburg-Essen, and Max Planck Institute for Polymer Research. The main point of this work is as follows:
The interaction of N two-level atoms with a single-mode light field is an extensively studied many-body problem in quantum optics, first analyzed by Dicke in the context of superradiance. A characteristic of such systems is the cooperative enhancement of the coupling strength by a factor of N1/2. In this study, we extended this cooperatively enhanced coupling to a solid-state system, demonstrating that it also occurs in a magnetic solid in the form of matter-matter interaction. Specifically, the exchange interaction of N paramagnetic erbium(III) (Er3+) spins with an iron(III) (Fe3+) magnon field in erbium orthoferrite (ErFeO3) exhibits a vacuum Rabi splitting whose magnitude is proportional to N1/2. Our results provide a route for understanding, controlling, and predicting novel phases of condensed matter using concepts and tools available in quantum optics.
And the Science journal introduces this work as: One of the earliest and most intensively studied problems in quantum optics is the interaction of a two-level system (an atom) with a single photon. This simple system provides a rich platform for exploring exotic light-matter interactions and the emergence of more complex phenomena such as superradiance, which is a cooperative effect that emerges when the density of atoms is increased and coupling between them is enhanced. Going beyond the light-matter system, Li et al. observed analogous cooperative effects for coupled magnetic systems. The results suggest that ideas in quantum optics could be carried over and used to control and predict exotic phases in condensed matter systems.
email: sxcao@shu.edu.cn (S.C.) | |
|
18 Sep 2024
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU Sonderseminar: 13:00 Uhr s.t., 01 122 Newton-Raum |
| A. Hirohata, Center for Science and Innovation in Spintronics, Tohoku University, Sendai 980-8577, Japan 2 Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan 3 Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany | |
In spintronics, magnetic tunnel and giant magnetoresistive junctions have been commonly used for magnetic recording, memories and sensors [1,2]. These junctions typically consists of a CoFeB/MgO/CoFeB trilayer. They satisfy the endurance required for fabrication and operation. For further improvement in their performance, namely their magnetoresistance ratios, Heusler alloys can be an ideal candidate due to their half-metallicity.
In this study, machine learning was used for the search of new Heusler alloys to satisfy the above requirements with maintaining the 100% spin polarisation at their Fermi level. As an example, a CoIrMnAl alloy was predicted to be ferromagnetic in experimental and theoretical studies [3,4]. The films were sputtered using ultrahigh vacuum magnetron sputtering on MgO(001) and Si substrates. The structural and magnetic characterisation was done by X-ray diffraction and transmission electron microscopy, and vibrating sample magnetometry, respectively. The optimised films were implemented in a magnetic tunnel junction for transport measurements, showing over 100% tunnelling magnetoresistance ratioThe material search is found to be useful by combining with ab initio calculations on alloys suggested by machine learning.
This work was partially supported by JST-CREST (No. JPMJCR17J5) and EPSRC (EP/V007211/1).
References
[1]A. Hirohata et al., J. Magn. Magn. Mater. 509, 166711 (2020).
[2]A. Hirohata et al., Front. Phys. 10, 1007989 (2022).
[3]T. Roy et al., J. Magn. Magn. Mater. 498, 166092 (2020).
[4]R. Monma et al., J. Alloys Comp. 868, 159175 (2021). | |
Sonderseminar | |
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26 Sep 2024
GRK 2516 Soft Matter Seminar
Uni Mainz 14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Julian Thiele, University of Magdeburg | |
(SFB 1552 Seminar Series) | |
| at Zoom | |
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02 Oct 2024
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU Sonderseminar: 13:00 Uhr s.t., Lorentz Room |
| Shilei Ding, Department of Materials, ETH Zürich, 8093 Zürich, Switzerland | |
Electronic devices based on charge motion have been well-studied and widely used in technological devices. However, the electrons can carry not only charges but also spin and orbital angular momentum. Nonequilibrium spin and orbital currents mediate the transfer of the angular momentum to the neighboring magnetic materials enabling the development of efficient spin orbitronic devices. Decoupling these currents from a flow of electronic charges opens opportunities for the electrical control of the magnetization. In this talk, I will first present the efficient spin torque in the magnetic insulators, including current-driving domain wall motion and the Dzyaloshinskii–Moriya interaction. In the second part of the talk, I will present the orbital torque and orbital Rashba-Edelstein magnetoresistance in the light metal system. The orbital-to-spin conversion plays a crucial role in the orbital torque, and the conversion layer can be ferromagnetic metal itself, 3d, 4f, and 5d non-magnetic metals. Our work indicates the efficient current-induced torque in the insulating system with a lower joule heating, and our results on orbital torques show that the magnitude of the orbital torque can be larger than the spin torque. The results further provide insight into the efficient current-induced torques with orbital current from low-cost, environmentally friendly light metals.
Biography
Shilei Ding received his B.S. in Physics from Peking University, China in 2016, and he received his Ph.D in Condensed Matter Physics from the School of Physics, Peking University (supervisor: Prof. Jinbo Yang). From 2017-2018 and 2019-2020, he was a guest Ph.D. student in the Lab of Prof. Mathias Kläui at Mainz University, Germany. He is now a Postdoctoral Researcher in the Lab of Prof. Pietro Gambardella at ETH Zurich, Switzerland. His research focuses on nonequilibrium spin and orbital current towards spin orbitronic devices, and he has published more than 30 papers in leading journals, including Physical Review Letters, Nano Letters, Advanced Materials, etc. | |
Sonderseminar | |
|
07 Oct 2024
Theorie-Palaver
Institut für Physik Sonderseminar: 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Soumen Kumar Manna, Indian Inst. Tech., Guwahati | |
Axion-like particles (ALPs), the pseudo-Goldstone bosons arising from the spontaneous breaking of global symmetry, are promising contenders for dark matter. The most extensively studied ALP production mechanism is known as misalignment mechanism, where ALP is presumed to initially remain frozen at a point in the field space until it begins oscillating around the potential minimum and behaves as cold dark matter (CDM). The oscillation initiates once the universe Hubble expansion rate falls below the ALP mass, defining the oscillation frequency. In this work, we examine how electroweak symmetry breaking (EWSB) affects ALP evolution, specifically through a higher order Higgs portal interaction. The interaction is observed to contribute partially to the ALP's mass during EWSB, thus altering oscillation frequencies and influencing the correlation between the scale of symmetry breaking and its mass. The novelty of this study lies in broadening the parameter space satisfying correct CDM relic density, facilitating future exploration through a diverse range of experimental avenues. | |
Sonderseminar | |
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22 Oct 2024
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| THEP Member, Mainz | |
Meet and Greet | |
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23 Oct 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Simone Burel, LUB Mannheim | |
Dealing with diversity is structurally anchored in most universities. In public discourse or in work contexts, a distinction is usually only made between the dimensions of diversity specified in the General Equal Treatment Act, such as e.g. age, gender, disabilities. One dimension that is often forgotten, but which is no less relevant for the future of work and our society, is neurodiversity. Neurodiversity means normalizing differences in people's mental states and not dividing them into “mentally ill” and “mentally healthy”. Here, Dr. Simone Burel also reports from her own experience and tells us about different types of neurodiversity (including impostor syndrome, depression, social phobia, anxiety disorder, panic disorder). She will open for us her treasure chest with tips and tricks to realize potential of neurodiverse persons. Slides here... | |
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24 Oct 2024
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
F. Schmid / G. Settanni / P. Virnau / L. Stelzl 14:30 Uhr s.t., Minkowski-Raum, 05-119, Staudingerweg 7 |
| Tomas Kasemets, Dr | |
Industry Talk on LADE | |
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Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:15 Uhr s.t., IPH Lorentzraum 05-127 |
| Asst.-Prof. Dr. Yuval Shagam, Israel Institute of Technology | |
The weak force is predicted to break the parity symmetry between left and right-handed chiral molecules, but so far the effect has eluded detection. We are developing a trapped chiral molecular ion version of the search for parity violation (PV). Our candidate molecule, CHDBrI+ is predicted to be preparable via state-selective ionization and to exhibit a large PV shift of a few Hz for the C-H bend vibrational transition, where the transition’s natural linewidth is narrower than the shift. Other transitions such as the C-H stretch are also predicted to have Hz level PV shifts between enantiomers.
We plan to probe the PV signature in a racemic, mixed-handedness ensemble of trapped CHDBrI+, using vibrational Ramsey spectroscopy. Our newly developed ion trap is integrated with a pulsed velocity map imaging detector to probe multiple internal state populations of the molecules by separating photo-fragment velocities. This technology will assist in overcoming the molecular complexity and help develop quantum control schemes for our molecule.
We will also discuss the advantages chiral molecules have in searches for new physics as well as the status of the experiment. | |
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28 Oct 2024
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 11:00 Uhr s.t., Curie Raum (03-431) |
| Ao Du, ETHZ Zürich, Switzerland | |
Antiferromagnets (AFM) hold significant promise as ideal candidates for high-density and ultrafast memory applications. Electrical manipulation of exchange bias has emerged as an effective solution to integrate AFMs into magnetic memories as active elements. With this motivation, we demonstrate the electrical detection of antiferromagnetism in three-terminal magnetic tunnel junctions (MTJs) via exchange bias. A polarity-dependent switching of the exchange bias, driven by spin-orbit torque, is observed with a switching time as short as 0.6 nanoseconds. By incorporating spin-transfer torque, we achieve a substantial reduction in the critical switching current density for spin-orbit torque, enabling reconfigurable AND/OR logic functionalities within a single device. Utilizing the stable multi-state behavior and auto-reset features of this MTJ, we propose an all-spin spiking neural network with a low recognition error rate. These findings hold potential for advancing high-performance memories and in-memory computing. | |
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29 Oct 2024
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Yan Luo, Peking U. | |
Axion-like particles (ALPs) are compelling candidates for new physics and have been extensively studied across a broad mass range, from sub-eV to hundreds of GeV. In this talk, I will discuss our recent works on ALP phenomenology across various experiments. First, I will present the potential for detecting ultralight ALP dark matter through radio telescopes that capture radio signals from axion-photon resonant conversion in the solar corona. We analyse data of the high-sensitivity radio telescope LOFAR, which provides stringent constraints on ALP interaction, contributing to the growing landscape of dark matter searches. I will then turn to collider and beam dump experiments, where we investigate the concurrent effects of ALPs, focusing on how ALP-photon and ALP-electron interactions jointly influence the detection of ALPs and demonstrate how current experimental limits are modified. | |
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Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Ekkehard Peik, Physikalisch-Technische Bundesanstalt Braunschweig | |
Motivated by the prospect of building a nuclear clock, we have demonstrated laser
excitation of the low-energy (8.4 eV) nuclear isomer in Th-229, using Th-doped
calciumfluoride crystals and a tabletop tunable laser system at 148 nm wavelength. A
nuclear resonance fluorescence signal has been observed in two crystals with different
Th-229 dopant concentrations, while it was absent in a control experiment using a
crystal doped with Th-232. The isomer radiative lifetime in the crystal is 630(15) s.
These results open the door towards laser Mössbauer spectroscopy and ideas from
"quantum nucleonics". An accurate nuclear clock would show high sensitivity to effects
of "new physics" for example in searches for violations of the Einstein equivalence
principle.
This is work done in a cooperation of PTB and TU Wien: J. Tiedau et al., Phys. Rev.
Lett. 132, 182501 (2024) | |
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30 Oct 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Markus Klute, KIT | |
This talk will explore the physics potential of the Future Circular Collider (FCC), a proposed particle accelerator at CERN, capable of reaching energies and luminosities beyond the capabilities of current machines.
We will discuss the FCC’s ability to probe the Standard Model with higher precision, its unique potential to explore the Higgs boson and discover new particles, and its role in addressing open questions in particle physics. The talk will illustrate how the FCC could shape our understanding of the universe at its most fundamental level.
Link to presentation slides:
https://www.dropbox.com/scl/fi/9l1v2wfsphp7glg9p42ku/2024-10-30-fcc.pdf?rlkey=jsxyz2tfi0bu6of99uofa2yc8&e=1&st=0j7yckpi&dl=0 | |
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31 Oct 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:15 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Dr. Simon Stellmer, Universität Bonn | |
Imagine two light fields propagating in opposite directions along a ring-shaped contour. When set into rotation, the constancy of the speed of light will induce a phase shift between the two light fields. This observation, known as the Sagnac effect, is a very powerful yet simple approach to measure rotation.
The first successful measurement of Earth's rotation via the Sagnac effect was performed by Albert A. Michelson and co-workers in late 1924, exactly 100 years ago. I will give a brief review of the historic work, present the current state of the art, and elaborate on potential applications and future developments. | |
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05 Nov 2024
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Maria Laura Piscopo, Nikhef, Amsterdam | |
Weak decays of heavy hadrons provide an excellent way to test the flavour and QCD structure of the SM. In this talk, I will present recent results and ongoing work on the study of both inclusive and exclusive decays, in both the beauty and charm sectors. Specifically, I will start by discussing the current status of the heavy quark expansion (HQE) and its application to the study of heavy hadron lifetimes. Then, I will describe the analysis of non-leptonic two body $B$- and $D$-meson decays using the framework of light-cone sum rules (LCSR), in light of the observed tensions in channels like $B^0 \to D^+ K^-$, and of the recent discovery of CP violation in the charm sector. | |
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Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Juliane Simmchen, University of Strathclyde, Glasgow | |
Colloids are a beautiful example of the unseen richness of our world, with structures
ranging from simple spheres to complex hierarchical structures that have fascinated
scientists for centuries. Interfaces on the other side are ubiquitous in nature, industry
and scientific setups. Passive colloids are known to show fascinating abilities such as
surfactant-like stabilization of emulsions, for example the well-known Pickering
emulsions.
When tiny colloids are forced out of equilibrium, whether by catalytic processes, thermal
effects or simple conjugation with biological objects, the resulting behaviour is
fascinating and often offers unexpected parallels to the macroscopic world. We study
both active and passive colloids in the presence of liquid interfaces, discovering rich
behaviour despite the technical challenges of visualisation.
[1] Wittmann, Martin, et al. "Active spheres induce Marangoni flows that drive collective
dynamics." The European Physical Journal E 44 (2021): 1-11.
[2] Sharan, Priyanka, et al. "Study of active Janus particles in the presence of an
engineered oil–water interface." Langmuir 37.1 (2020): 204-210. | |
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06 Nov 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Roman Pöschl, LAL Orsay, France | |
Calorimeters play a pivotal role in past, present and future experiments in particle physics. Final states of particle physics collision consist to a large fraction of jets. These jets are composed of electrons, photons and charged and neutral hadrons. A central requirement to meet scientific goals at future experiments is to keep the jet energy resolution at a level of 3-4% for jet energies between 45 GeV and around a TeV (or more). There are several proposal to meet this goal, by increasing the granularity of the calorimeters by dedicated precise measurements of hadrons and electromagnetic particles within a jet or by a combination of these features. This seminar will review the requirements to calorimeters in future experiments and the status and outlook on the current R&D to meet these requirements. The seminar will also sketch the potential to apply machine learning for calorimetry and how quantum sensing may dramatically change the design of future calorimeters.
Slides:
https://docs.google.com/presentation/d/1P0fRA6z8l1XNLxh8bBXHHB0a90VHrjt63EOvA7wNEFg/edit?usp=sharing Slides here... | |
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12 Nov 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Prem Piramanayagam, Nanyang Technological University, Singapore | |
Neuromorphic computing or brain-inspired computing is considered as a potential solution to overcome the energy inefficiency of the von Neumann architecture for artificial intelligence applications [1-4]. To realize spin-based neuromorphic computing practically, it is essential to design and fabricate electronic analogues of neurons and synapses. An electronic analogue of a synaptic device should provide multiple resistance states. A neuron device should receive multiple inputs and should provide a pulse output when the summation of the multiple inputs exceeds a threshold.
Our group has been carrying out investigations on the design and development of various synaptic and neuron devices in our laboratory. Domain wall (DW) devices based on magnetic tunnel junctions (MTJs), where the DW can be moved by spin-orbit torque, are suitable candidates for the fabrication of synaptic and neuron devices [2]. Spin-orbit torque helps in achieving DW motion at low energies whereas the use of MTJs helps in translating DW position information into resistance levels (or voltage pulses) [3]. This talk will summarize various designs of synthetic neurons synaptic elements and materials [4]. The first half of the talk will be at an introductory level, aimed at first-year graduate students. The second half will provide details of the latest research | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Antonio Pittelli, University of Turin & INFN Turin | |
Supergravity solutions with orbifold singularities contribute non-trivially to the quantum gravity path integral, unveiling new holographic correspondences. These solutions relate to supersymmetric quantum field theories (QFTs) defined on orbifolds with conical singularities, whose partition functions capture crucial physical insights such as dualities between different models and the entropy of accelerating black holes. From a mathematical perspective, the path integrals of these theories link to topological invariants of the underlying orbifolds, extending known results from smooth manifolds to singular spaces. This talk will present an investigation into supersymmetric QFTs on orbifolds with conical singularities, focusing on general circle fibrations over spindles. | |
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13 Nov 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Arthur Hebecker, University of Heidelberg | |
I will start with a brief introduction to the UV-problems of gravity and how string theory proposes to resolve them. As we will see, this implies extra dimensions and hence the possibility of different "compactifications", leading to very many possible 4d theories. The idea that more or less any 4d model can be found in this huge "Landscape" has more recently been challenged by the "Swampland" paradigm, proposing to search for general criteria for what can or can not occur in 4d effective theories having a consistent UV completion in quantum gravity. I will discuss some of the most important such "Swampland Conjectures": The "No-Global Symmetries", "Weak Gravity" and "Distance Conjecture". Finally, I will briefly review the phenomenologically very important but less established "de Sitter Conjecture". | |
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14 Nov 2024
GRK 2516 Soft Matter Seminar
Uni Mainz 10:30 Uhr s.t., HS 00.187, Biocenter 1, Hanns-Dieter-Hüsch-Weg 15 |
| Wolfgang Binder, University of Halle | |
TBA / Joint GK2516 & SFB1551 Seminar | |
| at Zoom | |
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Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:15 Uhr s.t., IPH Lorentzraum 05-127 |
| Dr. Lykourgos Bougas, HIM (Mainz) | |
Quantum computing is moving beyond its traditional mainframe infrastructure with the realization of room-temperature technologies powered by the nitrogen-vacancy (NV) centers in diamond. At Quantum Brilliance, we are at the forefront of this innovation, developing compact quantum accelerators based on NV centers—artificial atoms that enable fully functional qubits in a solid-state environment. This innovation holds the potential to make quantum computing not only more accessible but also more practical. Our mission is to deliver room-temperature quantum processors that can be deployed across a variety of environments, from centralized data centers to the network edge.
To achieve this, we are overcoming key technological challenges, such as the precise arrangement of NV centers at nanometer scales to enable magnetic coupling for multi-qubit operations across nodes. Quantum Brilliance addresses this using a breakthrough 'bottom-up' fabrication technique, leveraging atomically precise surface chemistry and lithography to build scalable diamond devices. Beyond scalability, we are also focused on advancing the performance, miniaturization, and manufacturability of these devices—crucial for achieving high-speed, high-fidelity spin control and efficient qubit readout in low-power, compact systems.
These technological advancements are positioning diamond quantum technologies as a leading force in the transition to compact, high-performance quantum computing and quantum information processing. With pre-production prototypes underway, Quantum Brilliance is on track to develop quantum accelerators with over 50 qubits, poised to outperform classical CPUs and GPUs in critical applications within the next five years.
In this presentation, I will explore the key innovations driving the performance, miniaturization, and scalability of diamond-based quantum technologies, and how these breakthroughs are set to transform the quantum computing landscape, enabling scalable, mass deployable quantum compute systems. | |
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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. | |
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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. | |
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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. | |
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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). | |
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aktuell
21 Nov 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:15 Uhr s.t., IPH Lorentzraum 05-127 |
| 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) | |
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Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 14:00 Uhr s.t., 01 122 Newton-Raum |
| 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) | |
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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. | |
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26 Nov 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Anna Watts, University of Amsterdam | |
Mapping Neutron Stars – Inside and Out | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Raoul Rontsch, University of Milan | |
TBA | |
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27 Nov 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Lorenzo Bianchini, University of Pisa, Italy | |
New W Boson Mass Measurement of CMS | |
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28 Nov 2024
GRK 2516 Soft Matter Seminar
Uni Mainz 10:30 Uhr s.t., HS 00.187, Biocenter 1, Hanns-Dieter-Hüsch-Weg 15 |
| Jurriaan Huskens, University of Twente | |
Multivalency describes many types of interfacial interactions in Nature. For example, hemagglutinin coat proteins of the influenza virus bind non-covalently to multiple sialyl-terminated carbohydrates (SLNs) of a host cell. This interaction is weakly multivalent in nature, and therefore it responds very sensitively to the density of carbohydrates on the cell surface and to the individual affinity of the interacting molecular partners. This behavior explains the large differences between virus affinities observed for mutations in the receptor binding domain.
A key aspect of the multivalent interaction of viruses at cell membranes is its strong, non-linear dependence on the receptor density displayed at the surface. We here show the development of surface gradients of receptor-modified supported lipid bilayers (SLBs) to visualize and quantify the receptor density dependence in one microscopic image. This technique is called “Multivalent Affinity Profiling”. The fitting of the data by a thermodynamic model allows quantification of the threshold density, comparison of binding selectivities for different virus strains, and thus offers a molecular and quantitative understanding of the supramolecular binding energy landscape. This supramolecular and nanoscopic picture links fundamental molecular aspects of binding to biological processes of antigenic drift and zoonosis.
At a more general level, chemically modified interfaces can be used to study complex (bio)chemical recognition processes, such as the binding of viruses and DNA. Exquisite receptor or probe density control is achieved through surface receptor gradients and by poly-L-lysine chemistry with control over grafting density. Multivalent recognition events are probed and controlled at surfaces and in solution by molecular engineering of the interfaces of the involved building blocks. These concepts can, amongst others, be used to control the self-assembly of vesicles and other materials building blocks and to develop a method to isolate the cancer biomarker hyper-methylated DNA.
(Co-hosted with SFB 1551 Seminar Series) Slides here... | |
| at Zoom | |
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Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:15 Uhr s.t., IPH Lorentzraum 05-127 |
| Dr. Claudiu Genes, MPI für die Physik des Lichts, Erlangen | |
Superradiance and subradiance are fundamental aspects of the open system dynamics of dense ensembles of quantum emitters exhibiting spontaneous emission rates well below or well above the rate for a single isolated system. At the purely theoretical level, superradiance has been first discussed by Dicke in 1954, in the context of accelerated decay of an ensemble of identical N initially inverted two-level quantum systems. In practice, such cooperative behavior associated with super- and subradiance at low excitation levels, has been observed in the 1930s by Jelley and Scheibe, in the context of molecular aggregates: unexpectedly large absorption cross-sections have been recorded for dye molecules. This has been later explained by Kasha in the 1960s as stemming from the alignment of the transition dipole moments of the many nanometer-spaced monomers forming the aggregate.
We analytically tackle such issues with methods of open quantum system dynamics, in particular quantum Langevin equations and master equations.
For the problem of Dicke superradiance we identify an exact analytical solution for the time evolution of the density operator, valid for any time t any number N of emitters.
In the direction of quantum optics with molecules, we provide analytical models and solutions for the excitation migration between collective electronic levels in molecular aggregates and for processes involving non-radiative transitions due to non-adiabatic couplings of potential electronic landscapes in single large organic molecules.
[1] R. Holzinger and C. Genes, Exact solution for Dicke superradiance, arXiv:2409.19040, (2024).
[2] R. Holzinger, N. S. Bassler, H. Ritsch and C. Genes, Scaling law for Kasha's rule in photoexcited molecular aggregates, J. Phys. Chem. A 128, 19, 3910 (2024).
[3] N. S. Bassler, M. Reitz, R. Holzinger, A. Vibók, G. J. Halász, B. Gurlek and C. Genes, Generalized energy gap law: An open system dynamics approach to non-adiabatic phenomena in molecules, arXiv:2405.08718 (2024). | |
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03 Dec 2024
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Daniel Schmitt, Frankfurt U. | |
QCD-sourced tachyonic phase transition in a supercooled Universe | |
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Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Andreas von Manteuffel, Universität Regensburg | |
Perturbative quantum field theory predicts complex phenomena at particle colliders from basic first principles. By comparing precise high energy data with precise theory predictions, one can probe the fundamental laws of nature down to very small distances, and identify possible signals of physics beyond the standard model of particles.
In this colloquium, I show how calculating higher order quantum corrections enables a concise interpretation of measurements at the Large Hadron Collider and other facilities. I illustrate how a better understanding of the underlying mathematical structures and the adoption of new computational techniques have pushed the frontier in theoretical predictions. Slides here... | |
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04 Dec 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Larisa Thorne, Johannes Gutenberg-University Mainz | |
Nearly 70 years since the neutrino was discovered, and 25 years since discovery of neutrino oscillations established its non-zero mass, the absolute neutrino-mass scale remains unknown.
Tritium beta decay endpoint measurements currently offer the best upper limit on the neutrino mass. A next-generation experiment with greater sensitivity must overcome one of the major systematics for this kind of measurement: the molecular nature of the beta source. Past and current tritium beta decay experiments use a molecular tritium source in which one of the tritium atoms undergoes decay. A fraction of the decay energy excites the molecule into rotational, vibrational, or electronic excited states; this causes broadening in the molecule's final state distribution (FSD), and has a smearing effect on the beta decay spectrum. In order to achieve a reduced systematic uncertainty due to this FSD smearing, next-generation experiments must switch to an atomic tritium source.
I will present an overview of the necessary steps to develop such an atomic tritium source, through the lens of the Project 8 experiment. This multi-institution development program includes dissociation and accommodation cooling down to 10K; further cooling to 10mK via magnetic evaporative cooling; and atom trapping using magnet arrays. In addition to this overview, I will focus on the multitude of tritium-compatible diagnostic tools being developed at JGU Mainz to measure atom flux, atom beam shape, and temperature. | |
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05 Dec 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:15 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Steffen Glaser, Technische Universität München | |
Analytical and numerical tools of optimal control theory (1) have found widespread applications in NMR and EPR spectroscopy, imaging, and in quantum information processing (2). In the last decade, these tools not only provided pulse sequences of unprecedented performance and capabilities, but also new analytical and geometrical insight and a deeper understanding of pulse optimization problems. The definition of the figure of merit for a pulse sequence is crucial for the optimization for a desired range of applications.
In addition to standard figures of merit for excitation, inversion and refocusing pulses, more general figures of merits have made it possible to significantly extend the range of applications. This will be illustrated for recent examples from the field of NMR and the control of trapped cold atoms (3). Furthermore, based on the DROPS (4) and BEADS (5) representations, novel intuitive visualization approaches have been developed to see the dynamics of multi-qubit systems in quantum information processing and beyond.
(1) N. Khaneja, R. Brockett, S. J. Glaser, Phys. Rev. A 63, 032308/1-13 (2001); N. Khaneja, S. J. Glaser, R. Brockett, Phys. Rev. A 65, 032301 (2002); N. Khaneja, T. Reiss, C. Kehlet, T. Schulte-Herbrüggen, S. J. Glaser, J. Magn. Reson. 172, 296-305 (2005).
(2) S. J. Glaser, U. Boscain, T. Calarco, C. P. Koch, W. Köckenberger, R. Kosloff, I. Kuprov, B. Luy, S. Schirmer, T. Schulte-Herbrüggen, D. Sugny, F. K. Wilhelm, Eur. Phys. J. D 69, 279/1-24 (2015); C. P. Koch, U. Boscain, T. Calarco, G. Dirr, S. Filipp, S. J. Glaser, R. Kosloff, S. Montangero, T. Schulte-Herbrüggen, D. Sugny, F. K. Wilhelm, Eur. Phys. J. Quantum Technology 9, 19/1-60 (2022).
(3) Z. Zhang, L. Van Damme, M. Rossignolo, L. Festa, M. Melchner, R. Eberhard, D. Tsevas, K. Mours, E. Reches, J. Zeiher, S. Blatt, I. Bloch, S. J. Glaser, A. Alberti, arXiv:2410.02452 [quant-ph] (2024); L. Van Damme, Z. Zhang, A. Devra, S. J. Glaser, A. Alberti, arXiv:2410.02452 [quant-ph] (2024).
(4) A. Garon, R. Zeier, S. J. Glaser, Phys. Rev. A 91, 042122 (2015); D. Leiner, R. Zeier, S. J. Glaser, J. Phys. A: Math. Theor. 53, 495301 (2020).
(5) D. Huber, S. J. Glaser, arXiv:2410.01446 [quant-ph] (2024). | |
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Seminar über Theorie der kondensierten Materie / TRR146 Seminar
F. Schmid / G. Settanni / P. Virnau / L. Stelzl 14:30 Uhr s.t., Minkowski-Raum, 05-119, Staudingerweg 7 |
| Jürgen Horbach, Prof. Dr. | |
We consider a class of non-standard, two-dimensional (2D) Hamiltonian
models that may show features of active particle dynamics, and
therefore, we refer to these models as active Hamiltonian (AH) systems.
The idea is to consider a spin fluid where -- on top of spin-spin and
particle-particle interactions -- spins are coupled to the particle's
velocities via a vector potential. Continuous spin variables interact
with each other as in a standard $XY$ model. Typically, the AH models
exhibit non-standard thermodynamic properties (e.g.~for temperature and
pressure) and equations of motion with non-standard forces. This implies
that the derivation of symplectic algorithms to numerically solve
Hamilton's equations of motion, as well as the thermostatting for these
systems, is not straightforward. However, one can make use of the fact
that for Hamiltonian systems the equipartition theorem holds, providing
a clear definition of temperature (note, however, that the temperature
is not given by the average kinetic energy in this case) [1]. We derive
a symplectic integration scheme and propose a Nos\'e-Poincar\'e
thermostat, providing a correct sampling in the canonical ensemble [2].
Results for two different AH models are presented: (i) A model proposed
by Casiulis et al. [3] shows transition from a fluid at high temperature
to a cluster phase at low temperature where, due to the coupling of
velocities and spins, a center-of-mass motion of the cluster occurs. The
claim in Ref. [3] that this cluster motion is reminiscent of real flocks
of birds has been challenged by Cavagna et al. [4]. (ii) We propose an
AH model where spins and velocities are coupled such that as a result
particles feel a generalized Lorentz force. We show that our model leads
to a collective motion of particle clusters that is closer to the
behavior of flocks of birds.
[1] K. Huang, Statistical Mechanics (John Wiley \& Sons, New York,
1987).
[2] A. Bhattacharya, J. Horbach, and S. Karmakar, arXiv:2409.14864
(2024).
[3] M. Casiulis, M. Tarzia, L. F. Cugliandolo, and O. Dauchot, Phys.
Rev. Lett. {\bf 124}, 198001 (2020).
[4] A. Cavagna, I. Giardina, and M. Viale, arXiv:1912.07056 (2019). | |
| at Zoom | |
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10 Dec 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Dierk Raabe, Max Planck-Institute for Sustainable Materials, Düsseldorf | |
Iron- and steelmaking stand for about 8% of all global greenhouse gas emissions, which qualifies this sector as the biggest single cause of global warming. This originates from the use of fossil carbon carriers as precursors for the reduction of iron oxides. Mitigation strategies pursue the replacement of fossil carbon carriers by sustainably produced hydrogen and / or electrons as alternative reductants, to massively cut these CO2 emissions, thereby lying the foundations for transforming a 3000 years old industry within a few years.
As the sustainable production of hydrogen using renewable energy is a bottleneck in green steel making, the gigantic annual steel production of 1.85 billion tons requires strategies to use hydrogen and / or electrons very efficiently and to yield high metallization at fast reduction kinetic.
This presentation presents progress in understanding the governing mechanisms of hydrogen-based direct reduction and plasma reduction of iron oxides. The metallization degree, reduction kinetics and their dependence on the underlying redox reactions in hydrogen-containing direct and plasma reduction strongly depend on mass transport kinetics, Kirkendall effects, nucleation phenomena, chemical and stress partitioning, the oxide's chemistry and microstructure, the acquired and evolving porosity, crystal plasticity, damage and fracture effects associated with the phase transformation phenomena occurring during reduction. Understanding these effects, together with external boundary conditions such as other reductant gas mixtures, oxide feedstock composition, pressure and temperature, is key to produce hydrogen-based green steel and design corresponding direct reduction shaft or fluidized bed reactors, enabling the required massive C02 reductions at affordable costs. Possible simulation approaches that are capable of capturing some of these phenomena and their interplay are also discussed. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Gaia Fontana, University of Zurich | |
TBA | |
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11 Dec 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Marco Cirelli, Laboratoire de Physique Théorique et Hautes Énergies (LPTHE) Jussieu CNRS & Sorbonne Université | |
For decades, we have been looking for Dark Matter in the form of WIMPs, but many other possibilities exist. Light DM, intended as having a mass between 1 MeV and about 1 GeV, is one of these possibilities, which is interesting both theoretically and phenomenologically. Testing it via Indirect Detection is more challenging than WIMPs, but X-ray measurements provide a very powerful handle. They currently impose stringent constraints, and allow in perspective to explore further this relatively new region of the parameter space. | |
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12 Dec 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:15 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Ruben de Groote, KU Leuven, Belgien | |
Laser spectroscopy techniques provide nuclear-model independent access to nuclear properties, such as the electromagnetic moments, spins and charge radii. Advances in radioactive ion beam instrumentation and laser technologies have enabled the study of a wide range of elements and isotopes, pushing out far from the valley of stability towards the drip lines. In this seminar, I will present experimental progress along two important frontiers.
I will discuss the use of methods based on laser ionization spectroscopy and how they have allowed us to reach exotic nuclei, such as 94Ag 52K, which have long been out of reach. The role of these measurements in furthering our understanding of the atomic nucleus will also be put into context. Besides using efficient laser ionization and particle detection methods, another important frontier is the precision frontier.
I will focus on ongoing research which aims to perform optical and radiofrequency spectroscopy of radioactive ions while they are trapped in a linear Paul trap. I will discuss the status and first commissioning results of a new setup currently under construction at the KU Leuven. | |
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17 Dec 2024
Physikalisches Kolloquium
Institut für Physik 16:15 Uhr s.t., HS KPH |
| Metin Tolan, Georg-August-Universität Göttingen | |
Die Star Trek-Physik - Warum die Enterprise 158 kg wiegt und andere galaktische Erkenntnisse | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Di Zhang, Technical University of Munich | |
TBA | |
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18 Dec 2024
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Camilo Garcia-Cely, IFIC Valencia, Spain | |
Detection Techniques of Gravitational Waves | |
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19 Dec 2024
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:15 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Dominique Sugny, Laboratoire Interdisciplinaire Carnot de Bourgogne, Dijon | |
We apply innovative tools coming from quantum optimal control theory to improve theoretical and experimental techniques in quantum technologies [1,2]. This approach allows us to explore and to experimentally reach the physical limits of the corresponding dynamics in the presence of typical experimental imperfections and limitations. After a pedagogical introduction to these techniques [3], different applications in quantum technologies will be described. Recent theoretical and experimental results for the control of a Bose-Einstein Condensate in an optical lattice will be presented [4].
[1]- Quantum optimal control in quantum technologies. Strategic report on current status, visions ans goals for research in Europe
C. P. Koch, U. Boscain, T. Calarco, G. Dirr, S. Filipp, S. Glaser, R. Kosloff, S. Montangero, T. Schulte-Herbruggen, D. Sugny and F. K. Wilhelm
EPJ Quantum Technol. 9, 19 (2022)
[2]- Introduction to the Pontryagin Maximum Principle for Quantum Optimal Control
U. Boscain, M. Sigalotti, and D. Sugny
PRX Quantum 2, 030203 (2021)
[3]- Introduction to the theoretical and experimental aspects of quantum optimal control
Q. Ansel, E. Dionis, F. Arrouas, B. Peaudecerf, S. Guérin, D. Guéry-Odelin and D. Sugny
J. Phys. B 57, 133001 (2024)
[4]- Quantum state control of a Bose Einstein condensate in an optical lattice
N. Dupont, G. Chatelain, L. Gabardos, M. Arnal, J. Billy, B. Peaudecerf, D. Sugny, D. Guéry-Odelin
PRX quantum 2, 040303 (2021) | |
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