Semesterübersicht Sommersemester 2022
Sommersemester 2022 - Wintersemester 2022/2023 - Sommersemester 2023
13 Apr 2022
SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Ran Cheng, University of California | |
Driving Exchange Mode Resonance as Adiabatic Quantum Motor with 100% Mechanical Efficiency | |
| at Zoom and SPICE YouTube Channel | |
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19 Apr 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Piet O. Schmidt, MPI für Dynamik und Selbstorganisation | |
Highly charged ions (HCI) have many favorable properties for tests of fundamental physics and as potential next-generation optical atomic frequency standards. However, up until recently the most accurate laser spectroscopy on any HCI was performed on the 17 Hz wide fine-structure transition in Ar13+ with 400 MHz resolution, lagging almost twelve orders of magnitude behind state-of-the-art optical clocks. We present the first coherent laser spectroscopy of an HCI using techniques developed in the context of quantum information processing with trapped ions. A novel quantum algorithmic cooling scheme has been developed and implemented, which reduces motional shifts to below the 10-18 level. We have performed an absolute frequency measurement, including a full error budget for the Ar13+ HCI clock, which demonstrates that HCI optical clocks with systematic uncertainty below 10-18 become feasible. Finally, prospects for 5th force tests based on isotope shift spectroscopy of Ca+/Ca14+ isotopes and the high-sensitivity search for a variation of the fine-structure constant using HCI will be presented. This work paves the way towards optical clocks based on highly charged ions with a high sensitivity to a change in fundamental constants and other tests of beyond standard model physics. | |
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20 Apr 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Steen Hannestad, Univ. Aarhus, Denmark | |
CANCELED // Neutrino physics in the era of precision cosmology | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Aleksei V. Kimel, Radboud University | |
Resolving chicken-or-egg causality dilemma for magneto-structural phase transition in FeRh | |
| at Zoom and SPICE YouTube Channel | |
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21 Apr 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., Lorentz-Raum 05-127 |
| Prof. Dr. Angela Wittmann, Institut für Physik, Universität Mainz | |
According to Moore’s law, the development of charge-based devices is fast approaching its limits. In response to this, spintronics has become one of the most promising alternatives. Its paradigm-changing nature lies in making use of the spin degree of freedom in addition to the electron’s charge and mass for encoding information. Particularly regarding the development of novel and versatile devices for different applications, tunable spintronic properties at hybrid interfaces in unconventional materials systems are of paramount interest.
In the first part of this talk, I would like to give a brief insight into spin currents in hybrid molecule-magnet systems. We will explore the unique tunability of spin injection and diffusion by molecular design. The second part will focus on unravelling the domain structure in antiferromagnetic thin films. | |
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25 Apr 2022
RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t. |
| Minhyong Kim, U. of Warwick | |
Quantum field theory clearly has its origins in the largely successful attempt to classify the fundamental building blocks of matter and the interactions between them. On the other hand, a number of practitioners have suggested that it should gradually develop into a general purpose mathematical toolkit, following an evolution roughly similar to calculus. I will describe in this talk applications of this general philosophy to arithmetic geometry. | |
| at Zoom, BigBlueButton | |
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Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Lukas Koch, Institut für Physik | |
T2K - From cross sections to the origins of everything | |
| at Zoom also available | |
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26 Apr 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Yuri Litvinov, GSI Darmstadt | |
The storage of freshly produced radioactive particles in a storage ring is a straightforward way to achieve the most efficient use of the rare species as it allows for using the same secondary ion multiple times. Employing storage rings for precision physics experiments with highly-charged ions (HCI) at the intersection of atomic, nuclear, plasma and astrophysics is a rapidly developing field of research.
The number of physics cases is enormous. The focus here will be on the most recent highlight results achieved within FAIR-Phase 0 research program at the ESR. First, the measurement of the bound-state beta decay of fully-ionized 205Tl was proposed about 35 years ago and was finally accomplished in 2020. Here, the ESR is presently the only instrument enabling precision studies of decays of HCIs. Such decays reflect atom-nucleus interactions and are relevant for atomic physics and nuclear structure as well as for nucleosynthesis in stellar objects. Second, the efficient deceleration of beams to low energies enabled studies of proton-induced reactions in the vicinity of the Gamow window of the p-process nucleosynthesis. After proof-of-principle studies on stable 124Xe ions, proton capture reaction on short-lived 118Te was successfully measured in the ESR. Here, the well-known atomic charge exchange cross-sections are used to constrain poorly known nuclear reaction rates.
The performed experiments will be put in the context of the present research programs at GSI/FAIR and in a broader, worldwide context, where, thanks to fascinating results obtained at the presently operating storage rings, a number of new exciting projects is planned. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Lennert Thormählen, Univ. of Heidelberg | |
The axion is much lighter than all other degrees of freedom introduced by the Peccei-Quinn mechanism to solve the strong CP problem. It is therefore natural to use an effective field theory (EFT) to describe its interactions. Loop processes calculated in the EFT may however explicitly depend on the ultraviolet cutoff. In general, the dimensionful couplings suggest to identify it with the Peccei- Quinn symmetry-breaking scale. An example are K+ → π+ + a decays that will soon be tested to improved precision and whose amplitude is dominated by the term logarithmically dependent on the cutoff. This talk will critically examine the adequacy of using such a naive EFT approach to study loop processes by comparing EFT calculations with ones performed in complete QCD axion models. In DFSZ models, for example, the cutoff is found to be set by additional Higgs degrees of freedom and to therefore be much closer to the electroweak scale than to the Peccei-Quinn scale. In fact, there are non-trivial requirements on axion models where the cutoff scale of loop processes is close to the Peccei-Quinn scale, such that the naive EFT result is reproduced. This suggests that the existence of a suitable UV embedding may impose restrictions on axion EFTs. We provide an explicit construction of a model with suitable fermion couplings and find promising prospects for NA62 and IAXO. | |
| at Zoom | |
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27 Apr 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Almudena Arcones, TU Darmstadt | |
In 2017, a multimessenger era started with the first gravitational wave detection from the merger of two neutron stars (GW170817) and the rich electromagnetic follow-up. The most exciting electromagnetic counterpart was the kilonova. This provides an answer to the long-standing question of how and where heavy elements are produced in the universe. The neutron-rich material ejected during the neutron star merger (NSM) undergoes an r-process (rapid neutron capture process) that produces heavy elements and a kilonova. Moreover, observations of abundances from the oldest stars reveal an additional r-process contribution of a rare and fast event, which could be core-collapse supernovae (CCSN) with strong magnetic fields, so called magneto-rotational supernovae (MR-SN). Now we can use NSM and CCSN as cosmic laboratories to test nuclear physics under extreme conditions and to understand the origin and history of heavy elements. We combine hydrodynamic simulations of NSM and MR-SN including state-of-the-art microphysics, with nucleosynthesis calculations involving extreme neutron-rich nuclei, and forefront observations of stellar abundances in the Milky Way and in orbiting dwarf galaxies. This opens up a new frontier to use the freshly synthesized elements to benchmark simulations against observations. The nucleosynthesis depends on astrophysical conditions (e.g., mass of the neutron stars) and on the microphysics included (equation of state and neutrino interactions). Therefore, comparing calculated abundances based on simulations to observations of the oldest stars and future kilonovae will lead to ground-breaking discoveries for CCSN, NSM, the extreme physics involved, and the origin of heavy elements. Slides here... | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Ilya Krivorotov, UCI | |
Planar Hall Torque | |
| at Zoom and SPICE YouTube Channel | |
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28 Apr 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., Lorentz-Raum 05-127 |
| Prof. Dr. Stephan Schlemmer, I. Physikalisches Institut, Universität zu Köln, Germany | |
Ions play a key role in the chemical evolution of our universe. The process of star and planet formation is tightly connected to the presence and abundance of these species as I will discuss in my presentation. Molecular spectra are diagnostic tools for various astrophysical environments and their temporal evolution. However, laboratory spectra of most ions relevant to astrophysics are not available. Moreover, predicted spectra from ab-initio theory are not nearly accurate enough to guide astrophysical searches. Therefore, laboratory spectra of molecular ions are needed. I will report on progress towards recording high-resolution spectra from the microwave to visible range using our unique and innovative methods of action spectroscopy in ion traps and how in some cases our traditional picture of molecular structure is challenged.
References
B.A. McGuire, O. Asvany, S. Brünken, and S. Schlemmer, Nature Review Physics (2020) 2, 402–410. | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 15:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Lukas Hauer, MPI – Polymer Research | |
Hydrogels are present in many medical and consumable products for their capability to hold water under a range of externally imposed stresses (e.g., mechanical). Here, we investigate the stability of two types of hydrogel coatings (thermoresponsive (poly-N-isopropylacrylamide, PNIPAm) and weakly charged (poly (acryl acid), PAA)) by steadily streaming silicone oil over them both, experimentally and numerically. We find that independent of the hydrogel's polymer properties or the flow conditions, the swollen coating depletes linearly over time. The linearity of the depletion indicates that diffusion drives water molecules from the hydrogel into the oil flow. However, process timescales indicate that water is not provided instantaneous: Water molecules are retained in the hydrogel, leading to a local non-equilibrium at the shared interface which throttles depletion. We model the molecule flux over the interface, using Kramers’ theory, and implement the obtained (thermal) non-equilibrium flux in mean-field framework, which we solve numerically. Results of our simulation and experiments do match, well. These findings let us deduce that depletion is unaffected by the properties of the hydrogel (charge, elasticity, etc.) but only a consequence of the chemical potential of water and the flowing silicone oil. Depletion can be tuned by matching chemical potentials between water and silicone to avoid depletion. | |
| at Zoom | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 15:00 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Jude Vishnu, JGU Physics | |
Thermo-sensitive hydrogels have attracted considerable attention in the field of bio chemistry and bio-medicine. Earlier works show that microfluidics can be used to create core-shell particle with decoupled elasticity and surface adhesiveness.However these experiments could not achieve proper control over the core-shell interconnectivity.We use MD simulations to understand and quantify the diffusive interpenetration of these shell polymers into a core gel. The simulation uses a Regular network to model the gel which is diffusively invaded via a polymer solution. We look into the interfacial profile and the ways to control this core-shell connectivity. The density profiles show a clear dependence of penetration on shell polymer concentrations. This is also seen in the degree of interfacial integration and diffusion depths. Finally the analysis of diffused free chain within the gel shows the emergence of large clusters leading to percolation.These results give us insight into how the factors like the core-shell polymer contact time, shell polymer concentration, etc can help us fine tune the core-shell connectivity in experiments. | |
| at Zoom | |
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29 Apr 2022
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 13:00 Uhr s.t., Minkowskiraum, 05-119, Staudingerweg 7 |
| Robin Bebon, University Stuttgart | |
Thermodynamic uncertainty relations for first passage fluctuations | |
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02 May 2022
RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t. |
| Murad Alim, Hamburg U. | |
BPS invariants of certain physical theories correspond to Donaldson-Thomas (DT) invariants of an associated Calabi-Yau geometry. BPS structures refer to the data of the DT invariants together with their wall-crossing structure. On the same Calabi-Yau geometry another set of invariants are the Gromov-Witten (GW) invariants. These are organized in the GW potential, which is an asymptotic series in a formal parameter and can be obtained from topological string theory. A further asymptotic series in two parameters is obtained from refined topological string theory which contains the Nekrasov-Shatashvili (NS) limit when one of the two parameters is sent to zero. I will discuss in the case of the resolved conifold how all these asymptotic series lead to difference equations which admit analytic solutions in the expansion parameters. A detailed study of Borel resummation allows one to identify these solutions as Borel sums in a distinguished region in parameter space. The Stokes jumps between different Borel sums encode the BPS invariants of the underlying geometry and are captured in turn by another set of difference equations. I will further show how the Borel analysis of the NS limit connects to the exact WKB study of quantum curves. This is based on various joint works with Lotte Hollands, Arpan Saha, Iván Tulli and Jörg Teschner. | |
| at Zoom | |
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03 May 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t. |
| Stefano Vitale, University of Trento | |
LISA is a space-borne gravitational wave (GW)observatory under development by the European Space Agency (ESA). It aims at the GW spectrum between a few tens of micro-Hz and a fraction of a Hz, which cannot be accessed by ground-based detectors. Such frequency range gives access to million solar mass sources at cosmological distances, and to non-transient GW astronomy of our Galaxy. LISA has been preceded by a precursor mission, LISA Pathfinder, that has successfully demonstrated the necessary space-time metrology.
The talk will review the science and achievements of LISA Pathfinder, the status of LISA, and some recent highlights on LISA science.
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| at Recording of the presentation | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Rodolfo Capdevilla, U. of Toronto and Perimeter Institute | |
The Fermilab Muon g−2 collaboration has recently released its first measurement of (g−2)μ. This result is consistent with previous Brookhaven measurements and together they yield a statistically significant 4.2σ discrepancy with the Standard Model prediction. New physics solutions to (g−2)μ feature light weakly coupled neutral particles or heavy strongly coupled charged particles. In this talk I present an experimental program of existing and proposed experiments that can completely cover the set of theories that explain this anomaly. | |
| at Zoom | |
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04 May 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Geraldine Servant, DESY Hamburg | |
It is usually assumed that the axion starts oscillating around its minimum from its initially frozen position. However, the early dynamics of the Peccei-Quinn field can induce a large kinetic energy in the axion field, which starts rotating during its early evolution, before it gets trapped in one minimum. This can modify the equation of state of the universe by triggering a kination era before the axion acquires its mass.
This imprints a smoking-gun gravitational-wave peak on the primordial gravitational-wave background in the sensitivity bands of LISA, ET, and CE. Future gravitational-wave observatories will thus offer a new window on axion models.
I will present explicit realisations. I will also discuss how this dynamics opens up the allowed parameter space for ALP dark matter and other observational consequences. Slides here... | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Oksana Chubykalo-Fesenko, CSIC | |
Modeling of magneto-thermodynamics phenomena | |
| at Zoom and SPICE YouTube Channel | |
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Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., HS Institut für Kernphysik |
| Prof. Florian Schreck, University of Amsterdam | |
Ultracold quantum gases are excellent platforms for quantum simulation and sensing. So far these gases have been produced using time-sequential cooling stages and after creation they unfortunately decay through unavoidable loss processes. This limits what can be done with them. For example it becomes impossible to extract a continuous-wave atom laser, which has promising applications for precision measurement through atom interferometry [1]. I will present how we achieve continuous Bose-Einstein condensation and create condensates (BECs) that persist in a steady-state for as long as we desire. Atom loss is compensated by feeding fresh atoms from a continuously replenished thermal source into the BEC by Bose-stimulated gain [2]. Our experiment is the matter wave analog of a cw optical laser with fully reflective cavity mirrors. The only step missing to create a continuous-wave atom laser beam is the addition of a coherent atom outcoupling mechanism. In addition this BEC may give us access to interesting driven-dissipative quantum phenomena over unprecedented timescales. The techniques we developed to create the continuous source of thermal atoms are also nicely suited to tackle another challenge: the creation of a continuously operating superradiant clock [3,4,5,6]. These clocks promise to become more rugged and/or more short-term stable than traditional optical clocks, thereby opening new application areas. In the second part of my talk I will present how we are developing two types of superradiant clocks within the European Quantum Flagship consortium iqClock [4,5,6]. | |
| at Zoom | |
Veranstaltungstag und -ort geändert |
09 May 2022
RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t. |
| Urs Schreiber, Prague U. | |
The talks begins with an exposition of higher equivariant principal bundle theory, using a convenient category/homotopy-theoretic approach. By way of example and application, I’ll then show how this provides a pleasantly transparent way to understand:
1. the CPT-twisting of equivariant K-theory, which has come to be known as the “10-fold way”,
2. the neglected twisting of equivariant K-theory by “inner local systems” appearing inside orbi-singularities.
I’ll close by briefly indicating how, under the interpretation of K-cohomology as D-brane charge, these two facts have remarkable consequences for the physics of exotic “defect branes” in string theory (arxiv:2203.11838). This is joint work with H. Sati.
ncatlab.org/schreiber/show/Anyonic+defect+branes+in+TED-K-theory Slides here... | |
| at BigBlueButton | |
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Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Yuriy Popovych, Institut für Physik | |
Timing of the Wavelength-shifting Optical Module | |
| at Zoom also available | |
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10 May 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Dr. Sebastian Raeder, GSI Helmholtzzentrum für Schwerionenforschung GmbH | |
The quest for long-lived isotopes of superheavy elements on the so-called "island of stability" has motivated interdisciplinary research in this area for almost 50 years. The heaviest elements are of interest to nuclear and atomic physicists as well as to chemists due to their peculiar properties. While nuclear shell structure effects are responsible for their very existence stabilizing them against spontaneous disintegration, the structure of their electronic shells is affected by strong relativistic effects leading to different atomic and chemical properties compared to their lighter homologs. The atomic structure can be probed by laser spectroscopy which is a powerful tool to unveil fundamental atomic and nuclear properties. The lack in atomic information on the heavy element of interest, the low production rates, and the rather short half-lives make experimental investigations challenging and demand very sensitive experimental techniques. Recent results with dedicated experimental investigations were obtained for fermium (Fm, Z=100) and nobelium (No, Z=102) isotopes which will be discussed together with the perspectives for laser spectroscopy investigations in even heavier elements. | |
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11 May 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Adi Bornheim, Caltech Pasadena, USA | |
Current and future high energy physics particle colliders can provide instantaneous luminosities of 10^34 cm-2s-1 and above. The high center of mass energy of 10 TeV and beyond, the large number of simultaneous collisions of beam particles in the experiments and the very high beam crossing rates pose significant challenges. At the same time, the breadth of physics studies carried out at these colliders is expanding continuously, ranging from searches over precision physics measurements to heavy ion physics.
To detect and reconstruct physics events, the detectors must maximize the information they capture on the final state particles. Adi Bornheim will discuss how timing information with a precision of around a few 10 ps can aid the reconstruction of the physics events under such challenging conditions. He will present how the CMS detector operating at the LHC in CERN will be upgraded to exploit the precision timing capabilities of the calorimeter and by the inclusion of a dedicated MIP timing detector. Slides here... | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Sang-Wook Cheong, Rutgers University | |
Magnetic Chirality | |
| at Zoom and SPICE YouTube Channel | |
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12 May 2022
GRK 2516 Soft Matter Seminar
Uni Mainz 15:45 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Christian Holm, University of Stuttgart | |
In my talk I will present our research on how to study the pH response of weak hydrogels. I will introduce our Grand Reaction ensemble method to realistically model the pH-response, and also several abstractions on the methodological level on how to treat charged networks in a reasonable time. I will give several example studies on strong as well as weak gels, on polyelectrolyte stars, and also present a solution to the recently observed giant pKa shift in weak polyelectrolyte brushes. | |
| at Zoom | |
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Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., Lorentz-Raum 05-127 |
| Prof. Dr. Christoph Becher, Universität des Saarlandes | |
Quantum bits based on solid-state spins are promising and potentially scalable systems for the implementation of quantum technologies ranging from quantum information processing to quantum-enhanced sensing and metrology. Ideally, they combine individually addressable spins with very long coherence times, optical emission spectra with narrow homogeneous and inhomogeneous broadenings and bright single-photon emission. In this respect, impurity-vacancy color centers in diamond based on group-IV elements (SiV, GeV, SnV, PbV) have emerged as interesting systems promising to combine all desired favorable properties.
Here, we report on recent experiments on SnV centers where we find promising optical and spin properties: The negatively charged SnV(-) center is a bright single photon emitter, showing a narrow inhomogeneous distribution of zero phonon lines in a high-temperature annealed sample and truly lifetime-limited transition linewidths down to 20 MHz. We explore the charge transition cycle upon resonant excitation which leads to shelving in the dark SnV(2-) state and find that illumination with a second light field in the blue spectral range leads to fast and efficient initialization into the desired negative charge state. The charge-stabilized SnV(-) center exhibits exceptional spectral stability with very small spectral diffusion (4 MHz on a homogenous linewidth of 25 MHz over 1 hour) and promising spin dephasing time (5 µs, measured via coherent population trapping).
We discuss possible applications in quantum communication, based on the prospects of coherent spin manipulation and generation of indistinguishable single photons, as well as in quantum sensing by exploiting the option of all-optical sensing schemes.
J. Görlitz et al., Coherence of a charge stabilised tin-vacancy spin in diamond, npj Quantum Inf. 8, 45 (2022). | |
| at Zoom | |
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16 May 2022
Theorie-Palaver
Institut für Physik 10:00 Uhr s.t., THEP seminar |
| Ennio Gozzi, Trieste | |
This seminar consists of a journey on the path-integral approach to classical mechanics and a short walk on “dreams in progress” regarding the possible role of the action in the dark matter and dark energy problems. | |
| at Zoom | |
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RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16:00 Uhr s.t. |
| Fabian Hahner, Universität Heidelberg | |
The pure spinor superfield formalism is a systematic way to construct supersymmetric multiplets from modules over the ring of functions on the nilpotence variety. After a short review of the technique, I present its derived generalization and explain how the derived formalism yields an equivalence of dg categories between multipets and modules over the Chevalley--Eilenberg algebra of supertranslations. This equivalence of categories is closely related to Koszul duality. If time permits, I will comment on applications to six-dimensional supersymmetry. | |
| at BigBlueButton | |
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17 May 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Heino Falcke, University of Radbourg | |
The inside of black holes is shielded from observations by an event horizon, a virtual one-way membrane through which matter, light and information can enter but never leave. This loss of information, however, contradicts some basic tenets of quantum physics. Does such an event horizon really exist? What are its effects on the ambient light and surrounding matter? How does a black hole really look? Can one see it? Recently we have made the first image of a black hole and detected its dark shadow in the radio galaxy M87 with the global Event Horizon Telescope. Detailed supercomputer simulations faithfully reproduce these observations. Simulations and observations together provide strong support for the notion that we are literally looking into the abyss of the event horizon of a supermassive black hole. The talk will review the results of the Event Horizon Telescope, the nature and meaning of the black hole shadow, its scientific implications and future expansions of the array. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Jack Holguin, Ecole Polytechnique | |
Final states in collider experiments are characterized by correlation functions of the energy flow operator - which plays the roll of an idealised calorimeter. In this talk, I will show that the top quark imprints itself as a peak in the three-point correlator at an angle determined by its mass and transverse momentum. This provides direct access to one of the most important parameters of the Standard Model in one of the simplest field theoretical observables.
The analysis I will present provides a new paradigm for a precise top mass determination that is, for the first time, highly insensitive to soft physics and underlying event contamination. | |
| at Zoom | |
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18 May 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Chris Hays, Oxford, England | |
The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After the observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 TeV center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. Slides here... | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Juan Carlos Rojas Sanchez, Institut Jean Lamour UL-CNRS | |
Ferrimagnetic spintronics and self-torque | |
| at Zoom and SPICE YouTube Channel | |
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19 May 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum (05-127) |
| Dr. Ronald Ulbricht, Max-Planck-Institut für Polymerforschung | |
The negatively-charged nitrogen-vacancy defect (NV–) possesses an interesting combination of spin and optical properties that can potentially be exploited in applications such as solid-state qubits, highly sensitive electric and magnetic field probes and single-photon emitters.
Within the diamond bandgap, the NV– centre forms an optically accessible two-level quantum system which consists of a spin-triplet ground state of 3A2 symmetry and a spin-triplet excited state of 3E symmetry. Two more electronic levels, both being spin-singlet states (1E and 1A1), are situated within the bandgap. NV centres can also exist in the neutral charge state (NV0). The predominantly utilized feature of the NV– centre is the spin-triplet 3A2 state that can be manipulated with microwave radiation and its spin state read out via the PL yield of the triplet transition as optically detected magnetic resonance (ODMR). Recently, photoelectric detection of magnetic resonance (PDMR) has been demonstrated as an alternative that utilizes state-selective ionization of NV– to NV0 and photocurrent detection. Despite being one of the best-studied solid-state defects, the non-equilibrium dynamics of NV centres are not yet fully understood, particularly with respect to charge conversion.
We present results using time-resolved spectroscopic techniques such as transient absorption spectroscopy, photocurrent spectroscopy and THz time-domain spectroscopy to investigate the dynamics of ensembles of NV centers in bulk diamond after photoexcitation by probing the transient response of its optical signatures. Two separately wavelength-tunable femtosecond pulses (450-1040nm) for excitation, combined with broadband spectral probing (400-1650nm) over timescales reaching from fs to ms enable us to probe all relevant optical transitions in a time-resolved fashion, providing a direct measure of complex processes such as photoionization and charge conversion. Variation of the concentration of single substitutional nitrogen (Ns) in different samples permits us to characterize their influence on NV dynamics.
We probe the electronic dynamics of both NV0 and NV– centres. For the latter one, we characterize the whole spin polarization cycle and find two additional localized electronic states. We find that recombination of electrons from the conduction band after photoionization of NV– via 3E proceeds through two distinct relaxation channels. Using photocurrent spectroscopy, we also experimentally determine the photon energy threshold for photoionization from 3E. | |
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23 May 2022
RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t. |
| Leonardo Rastelli, Stony Brook U. | |
I will describe some recent progress on the correspondence between four-dimensional ${\cal N=2}$ superconformal field theories (SCFTs) and two-dimensional vertex operator algebras (VOAs). In particular I will introduce the notion of the “Higgs scheme”, an extension by nilpotent elements of the standard Higgs variety of an ${\cal N=2}$ SCFT, which plays a natural role in the associated VOA.
Unlike the Higgs variety, theHiggs scheme appears to be a perfect invariant, i.e. it conjecturally fully characterizes the SCFT. | |
| at Zoom | |
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24 May 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Mirjam Cvetic, University of Pennsylvania, USA | |
In the past decades, String Theory has emerged as the prime candidate for quantum unification of electromagnetic, nuclear, and weak forces with gravitational ones It has shed light on important fundamental questions of theoretical physics, such as the microscopic structure of black holes and the geometric origin of particle physics. We review these developments, such as the introduction of extended objects - Dirichlet branes - and highlight the important geometric role these objects play in deriving the Standard Model of particle physics and the microscopic structure of black holes. We also highlight progress made in deriving particle physics from F-theory, a geometric domain of string theory at finite string coupling, and recent systematic exploration of the landscape of the quadrillion Standard Models with three families of quarks and leptons. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Stefan Stelzl, TU Munich | |
We consider matter density effects in theories with a false ground state. Large and dense systems, such as stars, can destabilize a metastable minimum and allow for the formation of bubbles of the true minimum. Interestingly these bubbles are not necessarily confined to the dense region, but can escape to infinity. This leads to a phase transition in the universe after the formation of stars, and therefore has significant impact on e.g. solutions to the electroweak hierarchy problem based on dynamical selection of the electroweak vacuum. We work out some of the phenomenological consequences of such density triggered late phase transitions and put new constraints on the parameter space of some benchmark relaxion models. | |
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25 May 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Mark Hindmarsh, Univ. Helsinki; Finland | |
Gravitational waves will be an important probe of physics beyond the Standard Model, as they would be produced at possible first order phase transitions in the early universe. I will discuss the characteristic spectrum of gravitational radiation from phase transitions, how it is connected to underlying physics, and prospects for probing physics beyond the Standard Model at the future space-based gravitational wave detector LISA. Slides here... | |
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30 May 2022
RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t., Heidelberg |
| Maxim Zabzine, Uppsala U. | |
Abstract: Motivated by M-theory, I will review rank n nn K-theoretic Donaldson-Thomas theory on a toric threefold and its factorisation properties in the context of 5d/7d correspondence. In the context of this discussion I will revise the use of the Duistermaat-Heckman formula for non-compact toric Kahler manifolds, pointing out some mathematical and physical puzzles. | |
| at Zoom, BigBlueButton | |
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Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Alexander Deisting, Institut für Physik | |
A gas TPC for neutrino physics | |
| at Zoom also available | |
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31 May 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Karin Schönning, University of Uppsala | |
The world around us consists of protons and neutrons – tightly bound quark systems that just like other hadrons are confined by the strong interaction. The processes occur at distances corresponding to a femtometer, i.e. 10-15 m, and generate almost 99% of the visible mass of the Universe. To describe these interactions quantitatively, belong to the most challenging problems in contemporary physics.
Hyperons – quark triplets just like the protons but containing at least one heavier strange or charm quark – can shed new light on this puzzle. Being unstable, hyperons reveal through their decays more about their inner properties than protons. In particular, the hyperon spin can be traced in weak, parity violating decays. This feature makes hyperons a powerful diagnostic tool.
In this talk, I will demonstrate how spin polarised and quantum entangled strange hyperons can be exploited to measure their structure and size at the femtometer scale. I will also present recent measurements from the BESIII experiment in China and discuss future opportunities offered by facilities world-wide. | |
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01 Jun 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Anke Biekötter, IPPP Durham, England | |
We have plenty of reasons to believe that there is physics beyond the Standard Model of particle physics. Currently, however, new fundamental physics is doing a very good job at hiding from us at high-energy experiments like the Large Hadron Collider (LHC) at CERN. The reason for this could be that potential new particles are too heavy to be directly detected at present experiments. In this talk, we will use effective field theory to describe the effects of heavy new fundamental physics at lower energy scales. Specifically, we will investigate what we can learn about new physics through a global analysis of LHC data. Slides here... | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Geoffrey Stephen Beach, MIT | |
Domain walls and skyrmions: From ferromagnets to ferrimagnets | |
| at Zoom and SPICE YouTube Channel | |
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02 Jun 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., Lorentz-Raum 05-127 |
| Prof. Dr. Peter Krüger, PTB Berlin | |
Magnetic fields are ubiquitous in nature and since a long time also in technology. Yet, there are many open questions, needs for research and emerging new applications. Standards need to be set or refined, and more accurate calibrations are required by industrial adopters of new technologies. A particular challenge and opportunity arise at the lowest end of the spectrum of magnetic fields. With demonstrated measurement sensitivities beyond the femtotesla (per root Hertz) scale, the neuronal activities of the brain following a peripheral nerve stimulus become detectable in a single trial, for example. While even the foundations of physics can be tested at the frontier of lowest metrological noise floors, a current trend is to make magnetic field measurement and imaging viable in application contexts beyond quantum physics laboratories. Here, we will discuss such developments in terms of sensor developments, measurement environments and key use cases. We will focus on atomic gas-based probes of DC and slowly varying magnetic fields. With trapped ultracold gases, high resolution field mapping can be achieved with relevance to material developments such as indium tin oxide replacements for next-generation touch screens and solar panels. On the other hand, cells containing thermal atomic vapours can provide highest field sensitivities as part of optically pumped magnetometers with use in clinical neurology or current-density imaging in electric vehicle batteries. | |
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Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 15:00 Uhr s.t., Minkowski room, 05-119, Staudingerweg 7 |
| Giovanni Settanni, Institut für Physik, Johannes-Gutenberg University Mainz | |
Multiscale simulations of nanomaterials for nucleic acid delivery | |
| at zoom | |
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07 Jun 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Ramin Golestanian, MPI Göttingen | |
There are many ways to study life, and one that is particularly appealing to physicists is regarding it as self-organized active soft matter that is away from equilibrium ``just the right way’’. In this Colloquium, I will discuss this notion, and provide a number of examples of how we can begin to put together simple systems - from basic ingredients that we fully understand - that would exhibit the kind of active behaviour we find in living systems. In particular, I will discuss the general class of chemical activity both as the source of non-equilibrium drive and the underlying mechanism for self-organization. Cells and microorganisms produce and consume all sorts of chemicals, from nutrients to signalling molecules. The same happens at the nanoscale inside cells themselves, where enzymes catalyze the production and consumption of the chemicals needed for life. In this colloquium, I will discuss a generic mechanism by which such chemically-active particles, be it cells or enzymes or engineered synthetic colloids, can "sense" each other and ultimately self-organize in a multitude of ways. A peculiarity of these chemical-mediated interactions is that they break action-reaction symmetry: for example, one particle may be repelled from a second particle, which is in turn attracted to the first one, so that it ends up "chasing" it. Such chasing interactions allow for the formation of large clusters of particles that "swim" autonomously. Regarding enzymes, we find that they can spontaneously aggregate into clusters with precisely the right composition, so that the product of one enzyme is passed on, without lack or excess, to the next enzyme in the metabolic cascade. Finally, I will discuss how breaking the action-reaction symmetry can allow a system described by two scalar fields to exhibit spontaneous breaking of time translation, time-reversal, space translation, and polar symmetries. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t. |
| Andreas Crivellin, PS and U. Zürich | |
Hints for the violation of lepton flavour universality (satisfied within the SM) have accumulated in recent years. In particular, deviations from the SM predictions were observed in semi-leptonic B decays (b->sll and b->ctau), in the anomalous magnetic moment of the muon (g-2), in leptonic tau decays and di-electron searches. Furthermore, also the deficit in first row CKM unitarity, known as the Cabibbo Angle Anomaly, can be interpreted as a sign of lepton flavour universality violation. In this talk I review the status of these anomalies and give an overview of the possible interpretations in terms of new physics models. | |
| at Zoom | |
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08 Jun 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Christian Ospelkaus, Univ. Hannover | |
Laser cooling and state manipulation are key techniques in modern-day atomic and molecular physics experiments, both for fundamental tests and quantum technology applications. While laser cooling was initially demonstrated in a Penning trap, it has seen relatively little use in Penning-trap precision measurements. Present-day Penning trap mass and g-factor precision measurements are now at a level where laser cooling and control can provide critical advances both for measurement speed and accuracy. Yet most species of interest in Penning trap precision measurements do not possess suitable internal structure for laser manipulation. A particularly challenging and rewarding system is the (anti-)proton, which is being investigated by precision experiments within the BASE collaboration. In this and similar cases, hybrid approaches are highly desirable, where a laser-cooled ion with well-known internal structure is used to control the particle of interest. As part of BASE, we are setting up a cryogenic Penning trap apparatus for sympathetic cooling of single (anti-)protons by laser-cooled 9Be+ ions. We discuss how quantum logic spectroscopy, as first proposed by Heinzen and Wineland in 1990 and first used in the context of single-ion optical clocks, can be implemented in this system, and present both sympathetic cooling and state manipulation techniques. We discuss our most recent experimental results, demonstrating ground state cooling of the 9Be+ ion in the Penning trap as the key enabling step for any quantum logic based state manipulation of (anti-)protons. Slides here... | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Helena Reichlova, TU Dresden | |
Spontaneous anomalous Hall response and altermagnetism explored in MnTe and Mn5Si3 | |
| at Zoom and SPICE YouTube Channel | |
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09 Jun 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., Lorentzraum 05-127 |
| Dr. Danila Barskiy, Johannes Gutenberg Universität | |
Nuclear magnetic resonance (NMR) is undergoing renaissance: the advent of hyperpolarization techniques allows enhancing weak nuclear signals by orders of magnitude, making possible measurements which were previously considered impractical, e.g., monitoring metabolism in vivo. Since large magnetic fields are no longer necessary to generate large nuclear magnetization, non-conventional signal detection approaches are now being considered as an alternative to conventional, inductive schemes. In my talk, I will focus on our recent work demonstrating that parahydrogen-based spin chemistry can be used for generating hyperpolarized analytes for low (<1 tesla) and ultralow-field (<100 nT) NMR. The presented method is applicable to a wide range of small molecules possessing exchangeable protons and have potential applications for chemical analysis and measuring NMR spectra from natural extracts and biological fluids using portable spectroscopic tools. | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 15:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Rodrique Badr, JGU, Physics | |
We present the results of molecular dynamics simulations of liquid droplets on polymer brushes infused with lubricant. As the amount of lubricant is increased, the system undergoes a transition where the droplet goes from uncloaked to cloaked, i.e. gets fully covered with lubricant. We quantify the cloak thickness, present a theoretical explanation of the phenomenon, and measure the effect of cloaking on contact angles and the wetting ridge. | |
| at Zoom | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 15:00 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Fabian Berressem, JGU, Physics | |
Ultra-coarse-graining of homopolymers in inhomogeneous systems | |
| at Zoom | |
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13 Jun 2022
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Stefan Schoppmann, PRISMA Detektorlabor | |
Opaque Scintillators | |
| at Zoom also available | |
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Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 16:00 Uhr s.t., TUK, 46/HS270 |
| Markus Ternes, RWTH Aachen | |
https://www.uni-kl.de/trr173/events/distinguished-lecture-series/summer-term-2022 | |
| at Zoom | |
Zoom ID: 699 4140 4654 with Passcode: PhyKo#2022 |
14 Jun 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Andrea Vinante, University of Trento | |
Levitated micro/nanoparticles are an excellent platform for very sensitive table-top mechanical experiments in the context of fundamental and quantum physics. Compared to conventional mechanical systems, they offer a higher degree of isolation from the environment and higher tunability. Levitated ferromagnets offer the additional benefit of being extremely sensitive to magnetic fields and rotations, suggesting a number of applications in the context of magnetic field sensing and fundamental physics. I will report on our efforts to levitate micromagnets by Meissner effect in a gravitational-superconducting trap, using SQUIDs as motion detectors. Preliminary measurements show that levitation can be realized in good agreement with the Meissner effect, with ultralow damping rate of rotational and translational modes in the range of microHz. I will discuss some possible applications, focusing on tests of wave function collapse models [1], exotic interactions beyond the standard model and magnetometry. Remarkably, a torque sensor based on a levitated micromagnet is expected to overcome the Standard Quantum Limit on magnetometry, and to surpass by orders of magnitude the Energy Resolution Limit, often proposed as a benchmark for quantum magnetometers. This goal may be achieved not only in the gyroscopic atom-like regime as previously argued, but also in the librational trapped regime [2].
[1] A. Vinante et al, Narrowing the Parameter Space of Collapse Models with Ultracold Layered Force Sensors, Phys. Rev. Lett. 125, 100404 (2020).
[2] A. Vinante et al, Surpassing the Energy Resolution Limit with ferromagnetic torque sensors, Phys. Rev. Lett. 127, 070801 (2021). | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Fernando Marchesano, Madrid, IFT | |
String theory has been used to construct models of particle physics and cosmology in which Quantum Gravity is automatically incorporated. Such models always present certain features, whose importance was up to now deemed secondary. But what if they were an actual imprint of Quantum Gravity into high energy physics?
The Swampland Programme aims to unveil the general constraints that Quantum Gravity imposes on effective field theories of particle physics and cosmology, in order to derive actual predictions. In this talk I will consider those proposals that describe the energy scales that appear all the way up to the Planck mass, describe their implications for models of high energy physics, and discuss the current open problems that stem from them. | |
| at Zoom | |
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15 Jun 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Ekkehard Peik, PTB Braunschweig | |
We use frequency comparisons between highly accurate optical clocks for tests of fundamental principles. In particular, the 171Yb+ optical clock based on an electric octupole transition between the S-ground state and the lowest excited F-level with a radiative lifetime of 1.58 years provides a favorable combination of low systematic uncertainty and high sensitivity to relativistic effects and potentially new physics. Using this system we have established improved limits for violations of local position invariance (in space and time), including the presently most stringent limits for temporal variations of the fine structure constant and the electron-proton mass ratio. I will give an outlook on the development of a 229Th nuclear optical clock that will open new perspectives for fundamental tests in the domain of nuclear physics. Slides here... | |
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Theorie-Palaver
Institut für Physik 10:00 Uhr s.t., Galilei room |
| Roberto Percacci, SISSA, Trieste | |
A scalar theory can have many Gaussian (free) fixed points, corresponding to Lagrangians of the form ‑\phi\box^n\phi. We use the non-perturbative RG to study the flow from the free theory with four derivatives (n = 2) to the free theory with two derivatives (n = 1), in the presence of a shift-invariant interaction. We show that the anomalous dimension changes continuously in such a way that at the endpoints the fields have the correct dimensions of the respective free theories. These results generalize to other values of n, as well as to nonlinear sigma models. | |
| at Zoom | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Liquiao Liu, MIT | |
Nonreciprocal transport and topological band structure through interactions of magnonic multilayers | |
| at Zoom and SPICE YouTube Channel | |
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20 Jun 2022
RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16:00 Uhr s.t. |
| Heeyeon Kim, Rutgers U. | |
We discuss path integral derivations of topologically twisted partition functions of 5d SU(2) supersymmetric Yang-Mills theory on M4 x S1, where M4 is a smooth closed four-manifold. Mathematically, they can be identified with the K-theoretic version of the Donaldson invariants. In particular, we provide two different path integral derivations of their wall-crossing formula for b_2^+(M4)=1, first in the so-called U-plane integral approach, and in the perspective of instanton counting. We briefly discuss the generalization to b_2^+(M4)>1. | |
| at Zoom | |
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Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 16:00 Uhr s.t., TUK 46/HS 270 |
| Sebastian Loth, University of Stuttgart | |
https://www.uni-kl.de/trr173/events/distinguished-lecture-series/summer-term-2022 | |
| at Zoom | |
Zoom ID: 699 4140 4654 and Passcode: PhyKo#2022 |
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 14:00 Uhr s.t., 01-128 (Galilei Room) |
| Benedikt Grüger, University Göttingen | |
We investigate the interaction of two paradigmatic ways of being out of equilibrium, aging and driving, in simple models of glassy dynamics. We specifically consider the Bouchaud model, where a system jumps between the numerous minima of a rough energy landscape in configuration space. As the temperature decreases, the system undergoes a dynamical phase transition, at which the relaxation time diverges. With an additional field, we then drive the system by biasing it's dynamics towards higher/lower jumping activity. We investigate the spectrum of the (biased) master operator in that framework, using a population dynamics algorithm based on cavity theory that allows us to deduce statements about the thermodynamic limit. Combining this with extensive diagonalization we identify novel regimes in the bias-temperature phase diagram that are distinguished by the occurrence of different kinds of eigenvector localization and are linked to the existence of a spectral gap. We also present methodological advances in the form of novel strategies for operating the population dynamics algorithm. | |
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21 Jun 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Dirk Uwe Sauer, RWTH of Aachen | |
Die netto CO2-Emissionen sollen in Deutschland bis 2045 auf Null gesenkt werden. Andere Ländern haben sich zum Schutz des Klimas auf ähnliche Ziele verpflichtet. Der Mobilitätssektor trägt in Deutschland mit rund 20% zu den Gesamtemissionen bei und hat anders als die meisten anderen Sektoren seit 1990 keine signifikanten Reduktionen zu verzeichnen. Neben Anstrengungen das Verkehrsaufkommen z.B. durch Verlagerung vom Auto auf die Schiene, den ÖPNV oder das Fahrrad zu verringern, sind elektrische Antriebskonzepte ein technisch realistischer Weg, der inzwischen auch mit Nachdruck weltweit in der Automobilindustrie verfolgt wird. In PKW setzt sich aktuell weltweit das Konzept des batterieelektrischen Fahrzeugs durch.
Entsprechend ist die Frage, wie der Stand der Batterietechnik ist, welche Materialsysteme aktuell und in absehbarer Zeit zum Einsatz kommen, wie es um die Sicherheit der Batterien und wie es um die Rohstoffverfügbarkeiten bestellt ist.
Gleichzeitig steigt der Speicherbedarf auch im Stromsystem, um die stark fluktuierende Stromerzeugung aus Windkraft- und Photovoltaikanlagen zu vergleichmäßigen. Auch hier werden in großem Umfang Batteriespeicher zum Einsatz kommen, an die aber andere Anforderungen als im Mobilitätsbereich gestellt werden.
Diskutiert werden auch die Aussichten von Batterietechnologien, die heute noch nicht in großem Umfang kommerziell eingesetzt werden und die Rolle von Wasserstoff und seinen Derivaten im Mobilitätsbereich. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Rodolfo Ferro, JGU-Mainz | |
The estimation of $\alpha$ at the electroweak scale is an important parameter required for electroweak precision tests. It is computed through a combination of $\e^+e^-\rightarrow\mathrm{hadrons}$ data plus perturbative QCD contributions. The combination of data and pQCD can be optimized to reduce the error on the prediction of $\alpha(M_Z)$. Here, I will study how different groups choose the theory/data splitting and compare the type of errors associated with each framework. Later, I will discuss the relation of the running of $\alpha$ with the one of the weak mixing angle. Finally light new physics which might affect the measurement of the weak mixing angle at low energies will be discussed. | |
| at Zoom | |
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22 Jun 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Clara Cuesta, CIEMAT Madrid, Spain | |
The combined result of a number of experiments demonstrated that neutrinos have mass and oscillate. However fundamental questions about neutrinos remain: Is the neutrino its own antiparticle? What is the absolute scale of neutrino masses? How are the three neutrino mass states ordered? Is the CP symmetry violated in the neutrino sector? Are there sterile neutrino species? Current and future neutrino experiments are designed with state-of-the-art technology to provide answers to these questions. In this colloquium, the status of two of these experiments will be presented. On one hand, the Deep Underground Neutrino Experiment (DUNE) is a next generation experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and beyond the standard model searches. DUNE will consist of a beam of neutrinos located at Fermilab (US), a near detector, and a far detector placed at Sanford Underground Research Facility 1,300 km away. The far detector will have a total mass of 70 kton of liquid argon and as a previous step the ProtoDUNE program is on-going at the CERN Neutrino Platform. On the other hand, the MAJORANA DEMONSTRATOR operated an array of germanium detectors searching for neutrinoless double-beta decay (0𝜈𝛽𝛽). The excellent performance of the detectors provided new exclusion limits on the searches for neutrinoless double-beta decay and other rare-events, such as dark matter and axions. Slides here... | |
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23 Jun 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., Lorentz-Raum (05-127) |
| Assoc. Prof. Dr. Hartmut Häffner, University of California, Berkeley, USA | |
I will discuss two experiments recently completed at UC Berkeley.
In the first, we couple two ions via image charged induced in a 0.6 mm long wire to each other. While the efforts were aimed at establishing the much needed interface between individual quantum processors, the coupling can be used to cool, control and detect particles not accessible laser control and are thus relevant for precision metrology as recently shown by the BASE collaboration for cooling (anti)protons.
In the second set of experiments, I will discuss a test of a nonlinear extension to quantum mechanics. Already in the early 80's, S. Weinberg and others were wondering whether the laws of nature at the quantum scale are nonlinear (Ann.Phys. (N.Y.), 194, 336-386 (1989)). Interest dropped rapidly when it was shown that those extensions violate causality. However, recently Kaplan and Rajendran (arXiv:2106.10576 [hep-th]) managed to add nonlinear and state-dependent terms without violating causality. Interestingly this extension rendered the existing experimental tests ineffective. I will discuss why a quantum mechanical object tied to a macroscopic object (such as an ion trap) provides a more stringent test to Rajendran and Kaplan's hypothesis and present experimental bounds ruling it out at the 1E-11 level. | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 15:00 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Melis Yetkin, MPI-Polymer Research | |
Evaporating dispersion drops from superamphiphobic surfaces opens a way to fabricate supraparticles (SPs) with complex structures. The structure formation can be controlled by tailoring the interaction forces between particles and process conditions. In this study, the structure of the SPs was investigated by tuning the shape of the primary building blocks and by the addition of surfactant sodium dodecyl sulfate (SDS). | |
| at Zoom | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 15:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Tasos Sourpis, JGU, Physics | |
TBA | |
| at Zoom | |
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27 Jun 2022
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Ralf Gugel, Institut für Physik | |
Impressions from CERN: Triggering Run 3 | |
| at Zoom also available | |
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RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t. |
| Sara Pasquetti, U. of Milano-Bicocca | |
We introduce an algorithm to piecewise dualise linear quivers into their mirror dual. The algorithm uses two basic duality moves and the properties of the S-wall which can all be derived by iterative applications of Seiberg-like dualities. | |
| at Zoom | |
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28 Jun 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Markus Rex, AWI Potsdam | |
Frozen at the North Pole - Expedition to the Epicenter of Climate Change
It was the largest expedition to the Arctic ever. In October 2019, the research icebreaker “Polarstern” allowed itself to be frozen solid in the Arctic sea ice in order to drift through the central Arctic for an entire year powered only by the natural flow of the arctic ice. Supported by six other ships as well as airplanes and helicopters, this is the first time that a modern research icebreaker vessel has reached the immediate vicinity of the North Pole in winter. Following in the footsteps of Fridtjof Nansen's historic research expedition from 1893-1896, the scientists explored the North Pole in greater detail than ever before, despite extreme cold, Arctic storms, an ever-changing ice landscape and the unprecedented challenges posed by the Corona pandemic. They achieved groundbreaking observations of climate processes in the central Arctic. This will enable them to better understand and predict the climate system. Project and expedition leader Markus Rex reports on the dramatic climate change in the Arctic and gives an insight into the process and the first results of this unique expedition. | |
THE LECTURE IS CANCELLED! |
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Manuel Reichert, University of Sussex | |
Over the past decades, the asymptotic safety scenario has matured into a viable contender for a consistent theory of quantum gravity. A pressing open question concerns the unitarity of the theory. I will present important steps towards tackling this issue and show the first direct computation of the graviton spectral function in asymptotically safe quantum gravity with a novel Lorentzian renormalisation group approach. The resulting graviton spectral function displays a massless one-graviton peak and a positive multi-graviton continuum with an asymptotically safe scaling for large spectral values, though being gauge-dependent. To understand the intricacies, I will contrast this to a perturbatively well-controlled computation of spectral functions in gauge theories with an infrared Banks-Zaks fixed point. I will indicate consequences for scattering amplitudes and unitarity. | |
| at Zoom | |
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29 Jun 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Helene Götschel, FU Berlin | |
Physics and astrophysics are strongly aligned with cleverness and masculinity. ‘Not surprisingly,
physics does an extremely good job at keeping people out’ (Anna Danielsson 2022). Therefore,
encouraging women and minorities to join is not enough. We need to understand and overcome the
gendered, classed and raced politics of knowledge-producing processes in STEM. In this talk we
reflect on the power of norms and exclusions in the culture, representation, and teaching of physics.
We look, for example, at communications in research labs, educational settings at universities,
physicists’ behavior at conferences, and contents of physics textbooks. In addition, we discuss
strategies to value and welcome diversity and equity in physics (teaching). Slides here... | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Ankit Disa, MPSD | |
How to engineer non-equilibrium crystal and magnetic structures with light | |
| at Zoom and SPICE YouTube Channel | |
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30 Jun 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., Lorentzraum 05-127 |
| Prof. Dr. Reinhold Walser, TU Darmstadt, Institut für Angewandte Physik | |
We will present the efforts to model realistic cold quantum gas experiments in (3+1)D for long times and large distances for the use in precision interferometry on ground, in the ZARM drop tower and in orbit. | |
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Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 15:00 Uhr s.t., Minkowski room, Staudingerweg 7 |
| Theo Odijk, Lorentz Institute for Theoretical Physics, University of Leiden | |
TBA | |
| at zoom | |
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01 Jul 2022
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 10:00 Uhr s.t., Medienraum 03-431, institute of Physics |
| Julian Skolaut, KIT, Germany | |
There has been a longstanding interest in the realization of machines, such as motors, on the nanoscale. First described in a thought experiment by Marian Smoluchowski in 1912 and popularized by Richard Feynman in 1962, the concept of the so-called Brownian ratchet has shown the physical limits in the realization of such nanomachines. Long after the theoretical description of such nanomachines, Bernard L. Feringa was able to design and synthesize a light-driven molecular motor and was awarded the Nobel Prize in 2016.
Taking a different approach by using the electric current in a scanning tunneling microscope (STM) as the stimulus, we present our results concerning a single molecular motor. Three anchoring groups fix the molecules to a Au(111) surface. The chiral functional group is connected via a rotatable axis and is supposed to perform a rotation in a preferred direction, proposed to be driven based on the chiral-induced spin selectivity (CISS) effect. This effect causes the electron spin of an injected current to be spin-polarized after passing through a chiral electric field, exerting a torque on the functional group via spin-orbit coupling.
Indeed, when positioning the STM tip above the molecule at a fixed position, we can observe directed rotation in the follwing way : We observe three distinguishable current levels, which are interpreted as metastable rotational states of the molecule. That way, two rotation directions can be defined. Via binomial tests, we verify that the surplus of rotational switches in one direction compared to the other is statistically significant.
In voltage and current dependent measurements, two interesting trends are observed. The rate of events decreases with increasing current and the asymmetry in the switching events varies non-monotonically with voltage. From voltage polarity dependent measurements, it is possible to extract more information on the underlying effect causing the directed rotation. | |
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04 Jul 2022
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Adrian Alvarez Fernandez, Institut für Physik | |
The Forward Feature EXtractor for the ATLAS Phase-II trigger upgrade | |
| at Zoom also available | |
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05 Jul 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Luciano Rezzolla, University of Frankfurt | |
Neutron stars: from macroscopic collisions to microphysics
I will argue that if black holes represent one the most fascinating implications of Einstein's theory of gravity, neutron stars in binary system are arguably its richest laboratory, where gravity blends with astrophysics and particle physics. I will discuss the rapid recent progress made in modelling these systems and show how the gravitational signal can provide tight constraints on the equation of state for matter at nuclear densities, as well as on one of the most important consequences of general relativity for compact stars: the existence of a maximum mass. Finally, I will discuss how the merger may lead to a phase transition from hadronic to quark matter. Such a process would lead to a signature in the post-merger gravitational-wave signal and open an observational window on the production of quark matter in the present Universe. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Sravan Kumar, Tokyo Institute of Technology | |
Cosmic inflation is an important paradigm of the early Universe which is so far developed in two equivalent ways, either by geometrical modification of Einstein's general relativity (GR) or by introducing new forms of matter beyond the standard model of particle physics. Starobinsky's R+R^2 inflation based on a geometric modification of GR is one of the most observationally favorable models of cosmic inflation based on a geometric modification of GR. In this talk, I will discuss in detail the fundamental motivations for Starobinsky inflation and present how certain logical steps in the view of its UV completion lead to the emergence of a gravity theory that is non-local in nature. Then I will establish how one can perform studies of the early Universe in the context of non-local gravity and what are the observational consequences in the scope of future CMB and gravitational waves. I will discuss in detail how non-local R^2-like inflation can be observationally distinguishable from the local effective field theories of inflation. Finally, I will comment on prospects of non-local gravity as a promising candidate for quantum gravity. | |
| at Zoom | |
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06 Jul 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Claude Duhr, Univ. Bonn | |
The referent will discuss advances in the understanding of the connection between scattering amplitudes and Feynman integrals on the one hand, and geometry and iterated integrals on the other. He will illustrate this connection with several results, ranging from the geometry underlying the high-energy limit in planar N=4 Super-Yang-Mills theory, to novel results relating Feynman integrals to the geometry of Calabi-Yau manifolds. | |
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07 Jul 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., Lorentz-Raum 05-127 |
| Prof. Dr. Svetlana Malinovskaya, Stevens Institute of Technology, New Jersey, USA | |
Atoms in their highly excited electronic states, referred to as Rydberg atoms, have extraordinary nonlinear optical properties. Such atoms are highly polarizable and interact with each other via the dipole-dipole or the van-der-Waals interactions. Owing to these interactions, Rydberg atoms in optical traps possess the condensed matter-like collective behavior. They serve as a viable platform to study quantum many-body physics. Spin degrees of freedom of trapped Rydberg atoms bring rich new physics including quantum magnetism, quantum phases, and entanglement - a crucial resource in many quantum information and quantum communication tasks. In this talk, I will present a study of alkali rubidium atoms trapped in an optical lattice and controllably excited to the Rydberg states by linearly chirped laser pulses [1]. I will introduce a quantum control methodology to create entangled states of two typical classes, the W and the Greenberger-Horne-Zeilinger (GHZ) [2]. I will show that the entangled states of Rydberg atoms can be used to create the multiphoton entangled radiation states in a cavity and in free space [3]. The methodology exploits chirped-pulse adiabatic passage and provides a key step toward the resolution of a general problem of creating entanglement in high-dimensional quantum entities. | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 15:00 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Bhuwan Poudel, MPI-Polymer Research | |
The distribution of nanoparticles (NPs) within the polymer brush is a crucial element that determines their applicability, such as in nanosensors. The brush properties, such as grafting density, thickness, etc., can be used to control the structure formation of NPs. Here, we are interested in studying the assembly formation of NPs, in particular, by tuning the brush properties. | |
| at Zoom | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 15:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Gokul Goving, JGU, Physics | |
TBA | |
| at Zoom | |
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11 Jul 2022
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Matei Climescu, Institut für Physik | |
Development of a calorimeter with high angular resolution | |
| at Zoom also available | |
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12 Jul 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Elena Aprile, University of Columbia | |
The XENON Dark Matter Project aims at the direct detection of Dark Matter WIMPs as they scatter off a liquid xenon target in a two-phase time projection chamber (TPC). With steadily increased target mass and lower background, the XENON experiments have set world-leading limits on a variety of WIMP interactions and over a broad mass range. I will present results from the first science data obtained with the new XENONnT experiment, which continues taking data at the Gran Sasso Underground Laboratory. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Myriam Mondragon, UNAM | |
We present models with an extended Higgs sector, three Higgs doublets, which have an underlying S3 flavour symmetry.
S3 is the smallest non-Abelian discrete group, corresponding to the permutation of three objects, which makes it naturally suitable for a flavour symmetry. We apply this symmetry "universally" to the fermionic and scalar sectors.
We review some previous results in the fermionic sector (quarks and leptons), as well as recent results in the Higgs sector derived from the minimization of the potential and the explicit calculation of the Higgs-Higgs and Higgs-gauge boson couplings. We show that in the exact alignment limit (when only one of the Higgs bosons couples to the gauge bosons), the results at tree level coincide exactly with the Standard Model ones. We present the allowed parameter space for the scalar masses in the two possible alignment scenarios, with some interesting consequences. We also present the results for a dark matter candidate coming from this type of models, with a fourth inert Higgs. | |
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13 Jul 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Anna Sótér, ETH Zürich, Switzerland | |
Despite the immense success of the Standard Model (SM), it is well known to be incomplete in describing Nature. Most obviously it is not incorporating gravity, and also falling short in explaining cosmological observations like the baryon asymmetry of the Universe, or the nature of dark matter and dark energy. Recent tensions concerning lepton universality are also persistent in the latest results of LHCb [1], or the muon g-2 experiment [2].
In our newly approved LEMING experiment at the Paul Scherrer institute we aspire to carry out next generation atomic physics and gravity experiments using muonium, which is an exotic atom consisting purely leptons, a muon and an electron (M = μ⁺ + e⁻) [3]. The result of a M gravity measurement would be a direct test of the weak equivalence principle using elementary (anti)leptons from two families, in the absence of large binding energies from the strong interaction.
We started this challenging task by developing a novel cold atomic M beam in vacuum using muon conversion in superfluid helium. The basis of this new concept relied on the measured behavior of exotic atoms in SFHe, a recent laser spectroscopy result using antiprotonic helium [4]. Our new tantalizing measurements with the newly synthesized cold M beam production put us on a path for increased precision in 1S-2S laser spectroscopy of M, and may pave the way for a free fall experiment, that would be the first direct measurement of the gravitational interaction using (anti)leptons.
References
[1]LHCb Collaboration, Nat. Phys. 18, 277–282 (2022)
[2]Muon g−2 Collaboration, Phys. Rev. Lett. 126, 141801 (2021)
[3]A. Soter and A. Knecht, SciPost Phys. Proc. 5, 31 (2021)
[4]A. Soter et. Al Nature volume 603, pages 411–415 (2022) | |
|
SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t. |
| Liza Herrera Diez, CNRS and Université Paris-Saclay | |
Magneto-ionics: using ionic motion to control magnetism | |
| at Zoom and SPICE YouTube Channel | |
|
14 Jul 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Dr. Robert Löw, GEPRIS Universität Stuttgart | |
The research and the spectroscopy of hot vapors carries great potential, ranging from fundamental research to robust applications in the context of quantum technologies.
In the past decades the spectroscopy of atomic and molecular gases at room temperature has lost some attention due to the focus on cold atomic systems. Still, due to their experimental simplicity, their robustness, and their fundamental nature, they hold the promise to realize real-world quantum devices. Their narrow-band transitions and high optical depths enable such vapor cell science to implement excellent sensors, reference and metrologic devices or building blocks in quantum optics.
In this talk I will focus on optical non-linearities induced by atom-atom interactions, either by highly excited Rydberg states or for low lying states via the resonant dipole-dipole interactions. These non-linearities are manifest at the single photon level and can be exploited to generate and process non-linear light fields. As a platform we us a variety of cell types, where the most advanced ones involve integrated photonic waveguides and microresonators. | |
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18 Jul 2022
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Michael Nieslony, Institut für Physik | |
Deployment and preliminary data of the first LAPPD in ANNIE | |
| at Zoom also available | |
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RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t., Heidelberg |
| Hossein Movasati, IMPA, Brasil | |
I will talk on a project which aims to develop a unified theory of modular and automorphic forms. It encompasses most of the available theory of modular forms in the literature, such as those for congruence groups, Siegel and Hilbert modular forms, many types of automorphic forms on Hermitian symmetric domains, Calabi-Yau modular forms, with its examples such as Yukawa couplings and topological string partition functions, and even go beyond all these cases. Its main ingredient is the so-called ‘Gauss-Manin connection in disguise’. The talk is based on the author's book with the same title, available in my webpage. | |
| at Zoom | |
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19 Jul 2022
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Andreas Schäfer, University of Regensburg | |
The EIC project ist rapidly approaching CD-2 stage (Critical Decision 2; approval of preliminary design, cost, and schedule) and a large fraction of the international hadron physics community is focusing on the opportunities the EIC will provide and the challenges it will pose for theory. Precision and scope of the EIC experiments will be unprecedented and matching both is a highly non-trivial task. As illustrations I will review some aspects of this multifaceted topic without any claim to completeness. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Mariana Grana, Institut de Physique Théorique | |
One of the biggest problems in string compactifications is the large number of massless fields associated to deformations of the internal geometry. These “moduli” get masses from fluxes wrapping non-trivial cycles on the manifold. Fluxes have an associated charge, which on a compact manifold has to satisfy tadpole cancelation conditions. The tadpole conjecture proposes that the charge induced by the fluxes needed to stabilise a large number of moduli grows linearly with the number of moduli. In this talk I will go over the basics of flux compactifications, explain the conjecture, present its motivation, supporting evidence and consequences. | |
| at Zoom | |
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20 Jul 2022
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Christoph Langenbruch, RWTH Aachen | |
Precision measurements of heavy flavour decays constitute powerful tests of the Standard Model of particle physics. New heavy particles beyond the Standard Model can significantly affect flavour observables through virtual quantum corrections. Precision measurements of these observables can reveal potential deviations from Standard Model predictions, and thereby probe energy scales far beyond the beam energies currently available at colliders.
The talk will focus on flavour observables that have recently shown tensions with Standard Model predictions, the so-called flavour anomalies. The referent will present the current experimental status of the anomalies, briefly discuss possible interpretations, and give prospects for their clarification in the near future. Slides here... | |
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21 Jul 2022
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., Lorentz-Raum 05-127 |
| Prof. Dr. Giovanna Morigi, Universität des Saarlandes | |
In this talk I will discuss the role of noise in determining the topology of a neural network, whose dynamics is governed by biologically inspired model. I will then give an outlook on how these concepts could be implemented for engineering quantum target dynamics via a noisy environment. | |
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30 Aug 2022
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 10:30 Uhr s.t., THEP Seminar Room 05-427 |
| Elizaveta Tremsina, MIT, USA | |
Atomistic Simulations of Distortion-limited High-speed Dynamics of Antiferromagnetic Skyrmions | |
| at Zoom | |
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31 Aug 2022
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 9:30 Uhr s.t., 03-431, Medienraum, Staudingerweg 7 |
| Aurélien Manchon, Aix-Marseille University, France | |
Exploring the potentials of spin-orbitronics | |
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01 Sep 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 |
| Jingsheng Chen, National University of Singapore | |
Symmetry Breaking by Materials Engineering for Spin-Orbit-Torque Technology | |
| at Zoom | |
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02 Sep 2022
SPICE-Spin+X Seminar
TUK and JGU Sonderseminar: 14:00 Uhr s.t., Medienraum (Staudingerweg 7) |
| Samindranath Mitra, editor of Physical Review Letters | |
The talk will seek to address the role that PRL plays in disseminating important scientific results and the impact of digitalisation and social media on this process. Attendees will also have an opportunity to engage in a Q&A session.
PRL was established in 1958. It is a peer-reviewed, scientific journal that is published 52 times per year by the American Physical Society. PRL is an internationally read physics journal, describing a diverse multidisciplinary readership. Dr Samindranath Mitra has been an editor of PRL for more than twenty years. Slides here... | |
| at Zoom | |
Sonderseminar | |
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09 Sep 2022
Theorie-Palaver
Institut für Physik 13:30 Uhr s.t., Minkowski room |
| Raymond Co, Minnesota U. | |
We established a paradigm where the (QCD) axion’s novel cosmological evolution, a rotation in the field space, can give rise to axion dark matter via kinetic misalignment and can generate the observed baryon asymmetry of the Universe via axiogenesis. The axion rotation also leads a kination era, leaving unique signatures in the primordial gravitational wave spectrum. For ultralight (QCD) axions, this cogenesis scenario makes intriguing predictions on axion properties more experimentally accessible than the conventional ones. For heavy and cosmologically unstable QCD axions, the predictions from axiogenesis point to regions that can be probed by neutrino experiments and long-lived particle searches. We will also discuss how the presence of an axion-muon coupling will facilitate such probes at, e.g., ArgoNeuT, DUNE, FASER 2, and SHiP. | |
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Theorie-Palaver
Institut für Physik 10:30 Uhr s.t., Minkowski room |
| Michael Robert Trott, Niels Bohr Institute, University of Copenhagen | |
In recent years, the effective field theory approach to the Standard Model, the SMEFT, has been used to study LHC data with ever increasing theoretical precision and sophistication. However, the complexity of this theory lead to several barriers to substantial theoretical progress. In particular, the explosion in the number of parameters in the SMEFT as a function of operator mass dimension, and the technical challenge or reformulating SM predictions consistently into the SMEFT were very serious problems. This called into question the possible success and value of the SMEFT physics program over the long term. I will discuss how these challenges have been overcome. The key point leading to this advance, is the understanding that the projection of curved scalar field spaces generated by the Higgs onto a naive flat field space understanding-- implicitly embedded into the usual SMEFT Lagrangian, and approach -- was the root cause of many problems, technical challenges and confusions. Many outstanding issues have now been addressed and immediately overcome by reformulating the SMEFT noting its curved scalar field space(s) - in the Geometric SMEFT. Some examples of the benefits of this approach will be presented, and explained. | |
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12 Sep 2022
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 11:00 Uhr s.t., Kaiserslautern building 46/270 |
| Xin Fan, University of Denver | |
Transversely-Polarized Spin Current Generation from Ferromagnetic Metals | |
| at Zoom | |
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21 Sep 2022
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 10:30 Uhr s.t., 05 127 Lorentz-Raum Staudingerweg 7 55128 Mainz |
| David P. Landau, The University of Georgia | |
Incommensurate Phases in the Two-Dimensional XY-Model with Dzyaloshinskii-Moriya Interactions | |
Postponed from 8.9.2022 |
26 Sep 2022
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Sebastian Ritter, Institut für Physik | |
Masterkolloqium: Studies to Optimize the Electromagnetic Calorimeter of the DUNE ND-GAr Detector | |
| at Zoom also available | |
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28 Sep 2022
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 10:30 Uhr s.t., Minkowskiraum |
| Prof. Noriyoshi Arai, Keio University | |
Coarse-grained molecular simulation for active water pumps inspired by biomolecules | |
|