Semesterübersicht Sommersemester 2020

02 Apr 2020

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau10:30 Uhr s.t., Newtonraum, 01-122, Staudingerweg 9
Bing Li, Postdoctoral researcher, Institute of physics, JGU Mainz

17 Apr 2020

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

SFB/TR49 - Prof. Dr. Elmers10:30 Uhr s.t., online lecture series - streaming link: https://conference.uni-mainz.de/meet/dion/JBQR5429
Merlin Pohlit, Uppsala University, Department of Physics and Astronomy

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

SFB/TR49 - Prof. Dr. Elmers15:00 Uhr s.t., online lecture series - streaming link: https://conference.uni-mainz.de/meet/dion/8VBKC6N9
Simon Moser, Uni Würzburg

21 Apr 2020

Theorie-Palaver

Institut für Physik14:30 Uhr s.t.
 Michele Redi, Florence U. and INFN I will describe the conditions under which the Peccei-Quinn phase transition of the QCD axion is first order. I will then show that in approximately conformal scenarios, both at weak and strong coupling, the PQ phase transition can lead to a gravity wave background that is within the reach of Ligo or future ground based experiments. at Zoom
22 Apr 2020

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

SFB/TR49 - Prof. Dr. Elmers10:30 Uhr s.t.
Nadejda Bouldi, Heidelberg University
Core level spectroscopies to study magnetic materials
at Skype for Business

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

SFB/TR49 - Prof. Dr. Elmers15:00 Uhr s.t.
Angela Wittmann, Massachusetts Institute of Technology
Spintronic phenomena at interfaces
at Skype for Business

23 Apr 2020

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

Institut für Physik14 Uhr c.t.
 Dr. Tobias Jenke, ILL Grenoble Neutrons are excellent probes to test gravity at short distances – electrically neutral and only hardly polarizable. Very slow, so-called ultracold neutrons form bound quantum states in the gravity potential of the Earth. This allows combining gravity experiments at short distances with powerful resonance spectroscopy techniques, as well as tests of the interplay between gravity and quantum mechanics. In the last decade, the qBounce collaboration has been performing several measurement campaigns at the ultracold and very cold neutron facility PF2 at the Institut Laue-Langevin in Grenoble/France. A new spectroscopy technique, Gravity Resonance Spectroscopy, was developed and realized, and snapshots of falling wavepackets of these gravitationally bound quantum states were recorded. The results were applied to test gravity at micron distances as well as various Dark Energy and Dark Matter scenarios in the lab, like Axions, Chameleons and Symmetrons. In my talk, I will review the experiments, explain key technologies and summarize the results obtained. at Zoom Meeting ID: 236 122 4872
27 Apr 2020

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik12:30 Uhr s.t.
Bernard Brickwedde/Jan Lommler, Institut für Physik
at Zoom

28 Apr 2020

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16 Uhr c.t.
 Magdalena Kowalska, CERN/ U Genf When we polarise the spins of unstable nuclei, their beta emission will be asymmetric, due to the parity non-conservation of the weak interaction. This feature has been used by our team in a variety of fields. It is a way to look for New Physics through the determination of the Vud matrix element of the CKM quark mixing matrix in nuclear mirror decays. In nuclear physics, in allows to apply an ultrasensitive type of NMR (called beta-NMR) to determine the magnetic dipole moments and electric quadrupole moments of short-lived nuclei. Recently, we have started applying beta-NMR to chemistry and biology, since its sensitivity is up to a billion times higher than in conventional NMR. In this talk I will introduce spin polarisation via optical pumping and beta-NMR principles. I will present our experimental setup located at CERN/ISOLDE. Finally, I will discuss the three scientific topics: Vud from 35Ar decay, magnetic moment of 26Na with ppm accuracy, and the interaction of Na with DNA G-Quadruplex structures . at Recording of the presentation
29 Apr 2020

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

SFB/TR49 - Prof. Dr. Elmers10:30 Uhr s.t.
Michael Slota, Department of Materials, University of Oxford, OX1 3PH, UK
Molecular Spin Nanostructures
at Skype for Business

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

SFB/TR49 - Prof. Dr. Elmers15:00 Uhr s.t.
Max Hänze, 1. University of Stuttgart, Institute for Functional Matter and Quantum Technologies, Stuttgart, Germany. 2. Max Planck Institute for Solid State Research, Stuttgart, Germany.
Spin Dynamics: from Microstructures to Individual Atoms
at Skype for Business

30 Apr 2020

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

Institut für Physik14 Uhr c.t., https://zoom.us/j/94520261050 (Passwort-Anfrage an "stuckker@uni-mainz.de")
 Dr. Karolina Kulesz, CERN, Geneve GammaMRI project aims to develop a new medical imaging modality able to overcome the limitations of existing imaging techniques and to combines their advantages. Gamma-MRI introduces the spatial resolution of MRI, the sensitivity of nuclear medicine (PET and SPECT) and possible clinical benefits of xenon isotopes [1,2]. At the same time, it eliminates drawbacks of the above-mentioned techniques. Our team is at present working on a proof-of-concept experiment. Gamma-MRI is based on the detection of asymmetric γ-ray emission of long-lived polarized nuclear states in the presence of magnetic fields [2]. The nuclei used in our study are long-lived nuclear isomers of Xe isotopes: 129mXe (T1/2 = 9 d),131mXe (T1/2 = 12 d) and 133mXe (T1/2 = 2 d) produced at the ILL high flux reactor in Grenoble or at ISOLDE facility at CERN [3]. The isomers of Xe are then hyperpolarized via collisions with laser-polarized rubidium vapor (Spin Exchange Optical Pumping) [4]. Once polarized and placed inside a magnetic field, they emit γ-rays whose direction of emission depends on the degree of spin polarization. Emitted radiation is acquired with CeGAAG crystals coupled to Si photodetectors and readout electronics compatible with strong magnetic fields, which are able to support very high count-rates. Once high polarization is successfully acquired, similar procedure can be used to record the spins’ response to rf pulses in gradient magnetic field, which is up to 105 more sensitive than usual signal pick-up in rf coils. References: [1] R. Engel, Master thesis 2018, https://cds.cern.ch/record/2638538. [2] Y. Zheng et al., Nature 537, 652 (2016). [3] M. Kowalska et al., Letter of Intent, CERN-INTC-2017-092 / INTC-I-205 (2017). [4] T. G. Walker and W. Happer, Rev. Mod. Phys. 69, 629 (1997).

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

SFB/TR49 - Prof. Dr. Elmers10:30 Uhr s.t.
Naëmi Leo, CIC nanoGUNE, Donostia, San Sebastian, Spain
Artificial Spin Ice: From Frustration to Computation
at Skype for Business

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

SFB/TR49 - Prof. Dr. Elmers15:00 Uhr s.t.
Alan Farhan, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto, Finland
Frustrated spin architecture: from macroscopically degenerate artificial spin ice to artificial spin glasses
at Skype for Business

04 May 2020

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik12:30 Uhr s.t.
Ralf Gugel, Institut für Physik
at Zoom

05 May 2020

Theorie-Palaver

Institut für Physik14:30 Uhr s.t.
 Filippo Sala, CNRS Paris Jussieu Sub-GeV Dark Matter particles upscattered by cosmic rays gain enough kinetic energy to pass the thresholds of large volume detectors on Earth. I will show how public Super-Kamiokande and MiniBooNE data already exclude previously allowed regions of both DM-electron and DM-nucleon interactions. I will then discuss search strategies and prospects at existing and planned neutrino facilities, such as Hyper-K, DUNE, IceCube and KM3NeT. at Zoom

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t.
 Joachim Peinke, Universität Oldenburg The current development of wind energy is summarised, and it is shown that wind energy has become one of the cheapest ways to produce electrical energy. From the perspective of a physicist there are several challenging research questions which arise, although wind energy systems have been used already over several centuries. A central point of this talk will be to show how fundamental research in physics can contribute to the modern development of wind energy systems. at Recording of the presentation
07 May 2020

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

Institut für Physik17 Uhr c.t., https://zoom.us/j/94520261050 (Passwort-Anfrage an "stuckker@uni-mainz.de")
 Prof. Dr. Monika Schleier-Smith, Stanford University, USA The dream of the quantum engineer is to have an “arbitrary waveform generator” for designing quantum states and Hamiltonians. Motivated by this vision, I will report on advances in optical control of long-range interactions among cold atoms. Our lab is exploring two approaches: photon-mediated and Rydberg-mediated interactions. By coupling atoms to light in an optical resonator, we generate tunable non-local Heisenberg interactions, characterizing the resulting phases and dynamics by real-space imaging. Notable observations include photon-mediated spin-mixing—a new mechanism for generating correlated atom pairs—and interaction-based protection of spin coherence. In a separate platform, we employ Rydberg dressing to induce Ising interactions in a gas of cesium atoms in their hyperfine clock states, enabling the realization of a Floquet transverse-field Ising model. I will discuss prospects in quantum simulation and quantum metrology promised by the versatility of optical control. Achtung: Uhrzeit geändert!
11 May 2020

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik12:30 Uhr s.t.
Simone Schuchmann, Institut für Physik
at Zoom

12 May 2020

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t., online (zoom oder BigBlueButton)
Jeff Hangst, Aarhus University
COLLOQUIUM CANCELLED!

COLLOQUIUM CANCELLED!

14 May 2020

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

Institut für Physik17 Uhr c.t., https://zoom.us/j/94520261050 (Passwort-Anfrage an "stuckker@uni-mainz.de")
 Prof. Dr. Kai-Mei Fu, Depts of Physics and Electrical and Computer Engineering, University of Washington, Seattle, USA Single defects in crystals, often termed “quantum defects”, are promising qubit candidates for quantum network applications. I will first provide an overview of the types of properties we seek in single defects, how we create these defects and how we measure them, illustrated with examples from my group’s research. I will then present the semiconductor-on-diamond integrated photonics platform my group is developing to scale networks of many entangled quantum defects. Achtung: Uhrzeit geändert!

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau10:30 Uhr s.t., Newtonraum, 01-122, Staudingerweg 9
Maike Jung, Institut für Physik
at Zoom

18 May 2020

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik12:30 Uhr s.t.
Antoine Laudrain, Institut für Physik
at Zoom

19 May 2020

Theorie-Palaver

Institut für Physik14:30 Uhr s.t.
 Alexander Ochirov, ETH Zurich In view of the recent observations of gravitational-wave signals from black-hole mergers, classical black-hole scattering has received considerable interest due to its relation to the classical bound-state problem of two black holes inspiraling onto each other. In this talk I will discuss the link between classical scattering of spinning black holes and quantum scattering amplitudes for massive spin-s particles. Starting at first post-Minkowskian (PM) order, I will explain how the spin-exponentiated structure of the relevant tree-level amplitude follows from minimal coupling to Einstein's gravity and in the $$s \rightarrow \infty$$ limit generates the black holes' complete series of spin-induced multipoles. The resulting scattering function will be shown to encode in a simple way the known net changes in the black-hole momenta and spins at 1PM order and to all orders in spins. Then I will move on to the new results at 2PM order for the case of aligned black holes' spins and discuss the current state of the art for classical black-hole scattering. at Zoom

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t.
 Jan Meijer, Universität Leipzig The key technology to fabricate quantum devices, i.e. devices that employ single atoms or defects as functional unit is the addressing of single atoms in a solid with high lateral resolu-tion. Whereas the manipulation of single atoms at the surface has been possible since several years, the three dimensional addressing in the bulk requires more effort. The combination of surface manipulation and overgrowth is one possibility but technologically very challenging. Ion beam implantation allows addressing single countable atoms inside a given solid with nanometer precision. To meet this goal we firstly need to focus or collimate the ion beam and to count the ions delivered to the sample. Our approach is to detect a single ion during fly-by using image charge detection and to deliver the ion with nanometer precision employ-ing a modified commercial FIB system. However, to create a deterministic quantum register based on NV centers a third requirement has to be considered: The implanted nitrogen atom has to be converted into an NV center with nearly 100% efficiency. Unfortunately, the creation of vacancies by ion impact is a statistical process and therefore not predictable. Additionally, the charge state of the NV center has to be converted into the negative state to make it functional. The talk will discuss the state of the art of single ion nano-implantation methods as well as new developments in material science to overcome the limitations encountered in the crea-tion of NV centers so far. at Recording of the presentation
25 May 2020

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik12:30 Uhr s.t.
Alexander Fritz/Seva Orekhov, Institut für Physik
at Zoom

26 May 2020

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t.
 Achim Rosch, Universität Köln Magnetic skyrmions are tiny, topologically quantized magnetic whirls stabilized by relativistic spin-orbit interactions. They couple extremely efficiently to charge-, spin- and heat currents and can be manipulated by ultra small forces. They are therefore promising candidates for, e.g., future magnetic memories. The coupling of skyrmions to electrons can efficiently be described by artifical electromagnetic fields. We explore how these fields can be measured. Phase transitions in and out of the skyrmion phase are driven by topological point defects which can be identified as emergent magnetic monopoles. at Recording of the presentation
28 May 2020

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

Institut für Physik14 Uhr c.t., https://zoom.us/j/94520261050 (Passwort-Anfrage an "stuckker@uni-mainz.de")
 Prof. Dr. Herwig Ott, Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Germany Ultracold quantum gases are usually well isolated from the environment. This allows for the study of ground state properties and non-equilibrium dynamics of many-body quantum systems under almost ideal conditions. Introducing a controlled coupling to the environment “opens” the quantum system and non-unitary dynamics can be investigated. Such an approach provides new opportunities to study fundamental quantum phenomena and to engineer robust many-body quantum states. I will present an experimental platform [1,2] that allows for the controlled engineering of dissipation in ultracold quantum gases by means of localized particle losses. This is exploited to study quantum Zeno dynamics in a Bose-Einstein condensate [3], where we find that the particle losses are well described by an imaginary potential in the system’s Hamiltonian. We also investigate the steady-states in a driven-dissipative Josephson array [4]. For small dissipation, the steady-states are characterized by balanced loss and gain and the eigenvalues are real. This situation corresponds to coherent perfect absorption [5], a phenomenon known from linear optics. Above a critical dissipation strength, the system decays exponentially, indicating the existence of purely imaginary eigenvalues. We discuss our results in the context of dissipative phase transitions. References [1] T. Gericke et al., Nature Physics 4, 949 (2008). [2] P. Würtz et al., Phys. Rev. Lett. 103, 080404 (2009). [3] G. Barontini et al., Phys. Rev. Lett. 110, 035302 (2013). [4] R. Labouvie et al. Phys. Rev. Lett. 116, 235302 (2016). [5] A. Müllers et al. Science Advances 4, eaat6539 (2018).

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau10:30 Uhr s.t., Newtonraum, 01-122, Staudingerweg 9
Prof. Dr. Hossein Eslami, Chemistry Dept. TU Darmstadt
Self-assembly of Janus particles
at Zoom, email settanni@uni-mainz.de

02 Jun 2020

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t.
 Laura Baudis, University of Zurich Neutrinos are the only known elementary particles that are Majorana fermion candidates, implying that they would be their own antiparticles. The most sensitive and perhaps only practical probe of the Majorana nature of neutrinos is an extremely rare nuclear decay process, the double beta decay without the emission of neutrinos. After an introduction to the physics of neutrinoless double beta decay, I will present the experimental techniques to search for this exceedingly rare process. I will show the latest results from leading experiments in the field, then discuss future projects and their prospects to probe the inverted neutrino mass ordering scenario. at Recording of the presentation
04 Jun 2020

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

Institut für Physik14 Uhr c.t., https://zoom.us/j/94520261050 (Passwort-Anfrage an "stuckker@uni-mainz.de")
 Dr. Hélène Perrin, Université de Paris 13, Sorbonne, Paris Cite, France In this talk, I will discuss the dynamics of a superfluid quantum Bose gas confined at the bottom of a shell rf-dressed trap. Weakly interacting quantum degenerate atoms present a superfluid behavior, characterized by several properties including the emergence of specific collective modes at low energy or the apparition of quantum vortices when the fluid is set into rotation. In the talk I will describe the collective dynamical behavior of the atoms confined in this very smooth potential, from the low excitation regime where the first collective modes are observed to the fast rotation limit where the bubble shape of the trap plays an essential role.
09 Jun 2020

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t.
Martin Fertl, JGU Mainz
Muon g-2: Comparing the Muon’s Clocks to Test the Standard Model of Particle Physics
at Recording of the presentation

Theorie-Palaver

Institut für Physik15:00 Uhr s.t.
 Elina Fuchs, Chicago U. & Fermilab Complex Yukawa couplings of the Higgs boson have interesting implications for Higgs production and decay rates, EDMs and CP violation for electroweak baryogenesis. I will present if there are viable regions fulfilling all of these three complementary constraints, for real and imaginary dimension-six terms of the tau, muon, top and bottom. After considering each flavor separately, I will show that combinations of several sources allow for cancellations in the EDM and an enhancement of the baryon asymmetry. at Zoom
15 Jun 2020

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

SFB/TR49 - Prof. Dr. Elmers16:00 Uhr s.t.
Prof. Dr. Oliver Gutfleisch, Material Science, Technical University Darmstadt, D-64287 Darmstadt, Germany
at Zoom

16 Jun 2020

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t.
 Joachim Mnich, DESY Over the last years, intense discussions on the international level have started on the future perspectives of particle physics after the LHC era. In Europe, CERN Council has initiated an update of the European Strategy, supposed to conclude in spring 2020. This schedule might slip because of the current Covid-19 pandemic, but some possible directions for the field have been identified in the community discussions. These include plans for Higgs factories to study this very peculiar particle to highest precision as well as ideas for future hadron colliders with a significantly higher energy reach than the LHC. All of these projects will require large resources and can only be realized through global collaboration. It is therefore important to formulate a global strategy for particle physics, including for instance the USA in which the community discussions (Snowmass process) are starting now – with results expected in about a year. The International Committee for Future Accelerators (ICFA), which includes members from all world, regions will provide a forum for discussions towards a global strategy. The talk will summarize the status of these discussions and try to provide an outlook into the future. at Recording of the presentation

Theorie-Palaver

Institut für Physik14:30 Uhr s.t.
 Gustavo Marques Tavares, Johns Hopkins U. In this talk I will discuss the effects of single derivative mixing in massive bosonic fields. In the regime of large mixing this leads to striking changes of the field dynamics, delaying the onset of classical oscillations and decreasing the effects of friction due to Hubble expansion. I will discuss how this can change the cosmological evolution of the axion field in the presence of primordial magnetic fields, and show that this increases the axion abundance allowing heavier axions to make up all of dark matter. at Zoom
18 Jun 2020

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

Institut für Physik14 Uhr c.t., https://zoom.us/j/94520261050 (Passwort-Anfrage an "stuckker@uni-mainz.de")
 Dr. Angela Papa, PSI, Villigen, Switzerland and University of Pisa/INFN, Italy Lepton flavor violation (LFV) research is currently one of the most exciting branches of particle physics due to its high sensitivity to new physics. The observation of neutrino oscillations has clearly demonstrated that neutral lepton flavor is not conserved. This implies that charged LFV (cLFV) processes, such as the µ⁺ --> e⁺γ decay or the µ⁺ --> e⁺ e⁺ e⁻ decay, can also occur in simple extended Standard Model (SM) versions (i.e. including Dirac neutrinos) which takes into account for neutrino oscillations, although strongly suppressed. On the other hand, Beyond SM (BSM) extensions strongly enhance the predictions for cLFV branching ratios. Therefore such decays are ideal probes for new physics. In this talk the current status of the MEGII and the Mu3e experiments will be given. The first will aim at searching for the µ⁺ --> e⁺γ decay with a sensitivity of approx. 6 x10⁻¹⁴ while the second will pursue the µ⁺ --> e⁺ e⁺ e⁻ − decay search with an ultimate sensitivity of 10⁻¹⁶. Both experiments will be hosted at the Paul Scherrer Institut (Villigen, Switzerland) which delivers the most intense low energy continuous muon beam in the world (up to few x10⁸ µ/s), the optimal choice for such a kind of search. It will be also discussed the potentialities of these apparatuses to search for more exotics processes.
22 Jun 2020

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum
Kristof Schmieden, Institut für Physik
at Zoom for now

23 Jun 2020

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t.
 Rafael Lang, Purdue University, Indiana, USA I will review the science case for dark matter, presenting the evidence from cosmology and astrophysics. As will thus become clear, dark matter has already been discovered - we just don't know yet what it is made of. The so-called direct detection of dark matter is a very promising approach to tackle this question. I will present the status of this field, including the recently announced results from XENON1T. at Recording of the presentation
24 Jun 2020

PRISMA Colloquium

Institut für Physik13:00 Uhr s.t., Lorentz-Raum 05-127, Staudingerweg 7
 Dieter Riess, Institute of Nuclear Chemistry A non-zero electric dipole moment of the neutron (nEDM) would violate CP symmetry, and thus would be an indication for a new source of CP violation, which might help to explain the matter to antimatter asymmetry in our universe. The nEDM collaboration has taken data at the Paul Scherrer Institute in 2015 and 2016 in order to improve on the previous limit dn < 3×10−26 ecm at 90% C.L. [1]. In total more than 54000 individual measurement cycles were recorded using Ramsey’s method of separated oscillating fields to measure the precession frequency of ultracold neutrons in electric and magnetic fields. The analysis of this dataset has been carried out in a blind fashion. The collaboration has un-blinded their result at the end of November 2019. The new result will be presented together with a detailed description of the experiment. [1]: J.M. Pendlebury et al. PRD 92, 092003 (2015) at Panopto Recording
25 Jun 2020

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

Institut für Physik14 Uhr c.t., https://zoom.us/j/94520261050 (Passwort-Anfrage an "stuckker@uni-mainz.de")
 Prof. Dr. Jakob Reichel, Laboratoire Kastler Brossel, ENS Paris, France Many if not all future quantum technologies are enabled by quantum correlations in a well-controlled many-particle system. In ensembles of atoms, ions and many other quantum emitters, such correlations can be generated with a high-finesse optical cavity. This approach is particularly promising for quantum metrology. I will present an experiment combining a compact trapped-atom clock on an atom chip and a fiber Fabry-Perot microcavity. This first "metrology-grade" spin squeezing experiment enabled us to produce spin squeezed states with unprecedented lifetime up to a second, and to observe a "quantum phase magnification" effect due to the subtle interplay of these many-particle entangled states with the exchange interaction that occurs in the trapped low-temperature gas.
29 Jun 2020

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

SFB/TR49 - Prof. Dr. Elmers16:00 Uhr s.t., der Raum wird separat angekündigt
Prof. Dr. Uwe Bovensiepen, CRC 1242 Non-Equilibrium Dynamics of Condensed Matter in the Time Domain
at Zoom

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum
Daniele Guffanti, Institut für Physik
at Zoom for now

30 Jun 2020

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t.
 Jo van den Brand, Nikhef The LIGO Virgo Consortium achieved the first detection of gravitational waves. A century after the fundamental predictions of Einstein, we report the first direct observations of binary black hole systems merging to form single black holes. The detected waveforms match the predictions of general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. Our observations provide unique access to the properties of space-time at extreme curvatures: the strong-field, and high velocity regime. It allows unprecedented tests of general relativity for the nonlinear dynamics of highly disturbed black holes. In 2017 the gravitational waves from the merger of a binary neutron star was observed. This discovery marks the start of multi-messenger astronomy and the aftermath of this merger was studied by using 70 observatories on seven continents and in space, across the electromagnetic spectrum. The scientific impact of the recent detections on nuclear physics will be explained. In addition key technological aspects will be addressed, such as the interferometric detection principle, optics, and sensors and actuators. Attention is paid to Advanced Virgo, the European detector near Pisa that recently came on-line. The presentation will close with a discussion of the largest challenges in the field, including plans for a detector in space (LISA), and Einstein Telescope, an underground observatory for gravitational waves science. at Recording of the presentation

Theorie-Palaver

Institut für Physik14:30 Uhr s.t.
 Matheus Hostert, University of Minnesota In light of the recent experimental progress in the study of neutral and charged kaon decays, I will discuss how $K_L$ decays can offer a strong probe of dark sectors, independently from the decays of their charged partner. This is motivated by a recent excess in $K_L \to \pi^0 \nu\overline{\nu}$ reported by the KOTO experiment, which, if confirmed, would indicate the existence of light or new exotic particles. The models I discuss can easily accommodate such signatures, with some examples containing a dark matter candidate. at Zoom
02 Jul 2020

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau10:30 Uhr s.t.
Ashreya Jayaram, Institut für Physik, JGU, PhD student
at Zoom

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

Institut für Physik14 Uhr c.t., https://zoom.us/j/94520261050 (Passwort-Anfrage an "stuckker@uni-mainz.de")
 Dr. Philipp Schindler, Institut für Experimentalphysik, Uni Innsbruck, Österreich I will review our effort to build scalable quantum information processors with trapped atomic ions. In particular, I will focus on experiments to benchmark quantum operations that allow to predict the performance of quantum error correction. I will then discuss how to adapt these operations and benchmarking techniques to characterize ultrafast dynamics in single molecular ions.
06 Jul 2020

Seminar about Experimental Particle and Astroparticle Physics (ETAP)

Institut für Physik12:30 Uhr s.t.
Elisa Ruiz-Chóliz/Phi Chau, Institut für Physik
Axions and ALPs searches - cancelled
at Zoom

This talk has been cancelled

07 Jul 2020

Physikalisches Kolloquium

Institut für Kernphysik, Remote Seminar16:15 Uhr s.t.
 Paul Dodds, University College London Hydrogen caused an energy revolution when it was introduced from the early 1810s.  Might we return to using hydrogen again in the future?  Paul will examine the potential future roles of hydrogen and fuel cells across the economy, including for vehicles, heating your home and office, powering industry, and integrating renewable electricity generation.  He will examine the innovation challenges and opportunities for hydrogen and fuel cells, from both engineering and economic perspectives.  Finally he will compare them with alternative low-carbon technologies to try to understand which of these roles are most likely to be realised. at Zoom (for more details see below)

Theorie-Palaver

Institut für Physik14:30 Uhr s.t.
 Yann Gouttenoire, DESY Cosmic strings (CS) are topological defects formed after spontaneous breaking of a U(1) symmetry. Remarkably, thanks to the scaling regime, CS loops constitute a long-standing source of Gravitational Waves (GW) and produce a flat GW spectrum during radiation domination, spanning many orders of magnitude in frequency. I will discuss reasons to be excited about the possible future detection of GW from CS by the next generation of GW interferometers, in order to bring light on the existence of non-standard cosmology before Big-Bang Nucleosynthesis starts and the related Beyond-Standard-Model physics. I will discuss the possibility to probe superstring theories with moduli scale up to 10^{10} GeV, heavy dark photon with kinetic mixing as low as 10^{-18}, heavy ALPs with masses between 1 GeV and 10^{10} GeV or PBHs below 10^9 grams. at Zoom
09 Jul 2020

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

Institut für Physik14 Uhr c.t., https://zoom.us/j/94520261050 (Passwort-Anfrage an "stuckker@uni-mainz.de")
 Dr. Claudiu Genes, MPI for the Science of Light, Erlangen Optical photons typically carry very little energy and momentum. Despite this, they can still be successfully employed to control the motion of various objects ranging from small molecules to macroscopic vibrating mirrors or membranes. We theoretically employ stochastic methods to show how light can be used to read out vibrations of nuclei in molecules [1] or to cool down the motion of photonic crystal mirrors [2] or membranes [3], close to their quantum ground state. [1] M. Reitz, C. Sommer and C. Genes, Langevin approach to quantum optics with molecules, Phys. Rev. Lett. 122, 203602 (2019). [2] O. Cernotik, A. Dantan and C. Genes, Cavity quantum electrodynamics with frequency-dependent reflectors, Phys. Rev. Lett. 122, 243601 (2019). [3] C. Sommer and C. Genes, Partial optomechanical refrigeration via multi-mode cold damping feedback, Phys. Rev. Lett. 123, 203605 (2019).
13 Jul 2020

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

SFB/TR49 - Prof. Dr. Elmers16:00 Uhr s.t., der Raum wird separat angekündigt
Prof. Dr. Martin Weinelt, CRC/TRR 227 Ultrafast Spin Dynamics
at Zoom