Physikalisches Kolloquium Mainz

Programm für das Wintersemester 2021/2022

Tuesdays, 16 Uhr c.t.

Institut für Kernphysik, Hybrid Seminar

Lecture room CO2, Chemistry, Duesbergweg 10-14
19.10.21Kirill Melnikov, TTP, Karlsruher Institute of Technology
To be announced
16 Uhr c.t., Staudinger-Hörsaal, Ackermannweg 10, MPI-P

Sonderseminar

The location of the first colloquium is Staudinger-Hörsaal, Ackermannweg 10, MPI-P

26.10.21Alfons Weber, University of Mainz
Neutrinos are the most abandon matter particle in the universe, but very little is known about them. Originally proposed by Pauli as an undetectable placeholder to save energy- and angular momentum conservation, they have come a long way and surprising us at every step. It is now known, that neutrinos have mass and that the mass- and interaction-eigenstates are not the same, which leads to a phenomenon called neutrino oscillations. The colloquium will report on the current knowledge on the field concentrating on accelerator based experiments and highlight future facilities, which will make precision experiments and might tell us, if neutrinos and anti-neutrinos behave the same or not. Differences between neutrinos and anti-neutrinos (CP-violation) may shed some light why our universe is matter dominated.
16 Uhr c.t., Hörsaal CO2 Chemie - Nord-Ost (2321) Duesbergweg 10 - 14

02.11.21Dr. Mickaël Rigault, CNRS/IN2P3
Type Ia Supernovae are powerful distance indicators that enable us to measure the recent expansion rate of the Universe and thereby derive the properties of dark energy. They are also key to directly measure the Hubble Constant H0, found to be incompatible with predictions based on the standard model of cosmology anchored by Cosmic Microwave Background data. Yet, despite 20 years of success, we still largely ignore the underlying mechanism responsible for the astrophysical event a Type Ia Supernovae is. This is now limiting further progress on measuring cosmological parameters and questions the accuracy of our measurements that now entire the era of high precision. In this presentation, I will introduce the derivation of cosmological parameters with Type Ia Supernovae (dark energy’s w and H0) and how the study of the correlation between Supernova's properties that of their hosts gives us critical information to improve their use as cosmological probes. I will finish by introducing the ongoing Zwicky Transient Facility survey that is new revolutionising the field and opening new area for SN Cosmology.
16 Uhr c.t., at Zoom

09.11.21Christian Smorra, University of Mainz
Precision tests of CPT invariance – one of the fundamental symmetries in the Standard Model – include high-precision comparisons of the charge-to-mass ratios and the magnetic moments of the proton and antiproton. The ERC project STEP aims to improve these measurements by developing transportable antiproton traps to eliminate the limitations imposed by the magnetic field fluctuations of the antiproton decelerator of CERN. Further, we target the development of more precise spectroscopy methods for the antiproton charge-to-mass ratio and the magnetic moment. To this end, we have developed a sympathetic cooling method based on coupled harmonic oscillators that allows to couple a single proton to a cloud of laser-cooled beryllium ions. Recently, we succeeded in cooling the proton to 15% of the environment temperature using an LC circuit to enhance the coupling strength to the beryllium ions [1]. The cooling method is applicable to a broad range of trapped particles independent of the charge, and can be applied also to antiprotons, highly-charged or molecular ions. We further discuss the prospects of decreasing the temperature down to the 10 mK level in presence of the heating from the LC circuit and frequency uncertainties and drifts. A further decrease in temperature would greatly reduce the uncertainty of proton/antiproton magnetic moment measurements, and improve tests of CPT invariance in the baryon sector, and searches for dark matter particles, such as axions [2, 3] or millicharged particles [4]. [1] M. Bohman et al., Nature 596, pages 514–518 (2021). [2] C. Smorra et al., Nature 575, pages 310–314 (2019). [3] J. A. Devlin et al., Phys. Rev. Lett. 126, 041301 (2021). [4] D. Budker et al., arXiv:2108.05283 [hep-ph] (2021).
16 Uhr c.t., Hörsaal CO2 Chemie - Nord-Ost (2321) Duesbergweg 10 - 14

16.11.21Hartmut Löwen, Universität Düsseldorf
Ordinary materials are "passive" in the sense that their constituents are typically made by inert particles which are subjected to thermal fluctuations, internal interactions and external fields but do not move on their own. Living systems, like schools of fish, swarms of birds, pedestrians and swimming microbes are called "active matter" since they are composed of self-propelled constituents. Active matter is intrinsically in nonequilibrium and exhibits a plethora of novel phenomena as revealed by a recent combined effort of statistical theory, computer simulation and real-space experiments. After an introduction into the physics of active matter focussing on biological and artificial microswimmers as key examples of active soft matter [1], a number of single-particle and collective phenomena in active matter will be adressed including novel structures like "rotelles" [2] and "active droploids" [3]. [1] For a review, see: C. Bechinger, R. di Leonardo, H. Löwen, C. Reichhardt, G. Volpe, G. Volpe, Active particles in complex and crowded environments, Reviews of Modern Physics 88, 045006 (2016). [2] C. Scholz, A. Ldov, T. Pöschel, M. Engel, H. Löwen, Surfactants and rotelles in active chiral fluids, Science Advances 7, eabf8998 (2021). [3] J. Grauer et al, Active droploids, arXiv:2109.10677
16 Uhr c.t., at Recording of the presentation

23.11.21Rainer Blatt, Innsbruck
In this talk, the basic functional principles of quantum information processing are reviewed and the state-of-the-art of the Innsbruck trapped-ion quantum computer is reported. With strings of trapped ions, we implement a quantum information processor and perform quantum operations. We present an overview on the available quantum toolbox and discuss the scalability of the approach. The quantum way of doing computations is illustrated with analog and digital quantum simulations. Employing universal quantum computations, we investigate the dynamics of the Lattice Schwinger model [1], a gauge theory of 1D quantum electrodynamics and using a hybridclassical ansatz, we determine steady-state properties of the Hamiltonian [2]. Using tailored quantum operations, we obtain optimized measurements for spectroscopy [3]. [1] E. A. Martinez et al., Nature 534, 516 (2016). [2] C. Kokail et al., Nature 569, 355–360 (2019). [3] C. Marciniak et al., arXiv:2106.01860 (2021).
16 Uhr c.t., at Slides

30.11.21Achim Schwenk, Technische Universität Darmstadt
The strong interaction described by quantum chromodynamics gives rise to the formation of hadrons and nuclei that constitute the baryonic matter in the Universe and governs the densest matter in neutron stars and highest temperatures reached in compact object mergers. Combined with the electroweak interaction, it determines the structure and properties of all nuclei in the nuclear chart in a similar way as quantum electrodynamics shapes the periodic table of elements. However, big science problems of the strong interaction remain unsolved, especially regarding the structure of extreme neutron-rich matter in the laboratory and stars. New facilities for rare isotopes will discover over a thousand new isotopes, getting as close as possible to the nuclei in the Universe's heavy-element nucleosynthesis pathway. On the theoretical side, there are impressive advances towards a unified description of all nuclei and matter based on effective field theories of the strong interaction combined with powerful many-body methods. In this colloquium, we will discuss the advances, status and challenges in strongly interacting matter, with a focus on how the nuclear chart emerges from nuclear forces and on the physics of neutron stars and neutron star mergers.
16 Uhr c.t., at Recording of the presentation

aktuell

07.12.21Edda Gschwendtner, CERN

Pushing to new particle energy fronters with plasma wakefield acceleration 

The construction of ever larger and costlier accelerator facilities has its limits, and new technologies will be needed topush the energy fronTer. Plasma wakefield acceleraTon is a rapidly developing field which appears to be a auspiciouscandidate technology for future high-energy acceleratorsproviding acceleraTon gradients a factor 10 to 1000 larger thanin convenTonal radio-frequency metallic caviTes used in current accelerators.This presentation introduces the plasma wakefield acceleration technology, shows the technological challenges, gives anoverview of the state of the art and shows promising results on the example of the advanced proton driven plasmawakefield experiment, AWAKE, at CERN.
16 Uhr c.t., at Zoom

zukünftige Termine
14.12.21Dr. Benjamin Dönigus, Goethe-Universität Frankfurt
The high collision energies reached at the Large Hadron Collider (LHC) at CERN lead to significant production rates of fragile objects, i.e. objects whose binding energies are small compared to the average kinetic energy of the particles produced in the system. Such objects are, for instance, light (anti-)nuclei and (anti-)hypernuclei. The most extreme example here is the hypertriton, a bound state of a proton, a neutron and a lambda, where the separation energy of the lambda is only around 130 keV. These states, from the anti-deuteron up to the anti-alpha nuclei, are nevertheless created and observed in the hot + rough environment of proton-proton and heavy-ion collisions at the LHC. The reached temperaturesarehigher than156 MeV, corresponding to 1.8 x1012K.Selected highlights ofmeasurements of these fragile objects will be presented.
16 Uhr c.t., Hörsaal CO2 Chemie - Nord-Ost (2321) Duesbergweg 10 - 14

04.01.22Dr. Dionysis Antipas, University of Mainz
Parity violation in atoms
16 Uhr c.t., Hörsaal CO2 Chemie - Nord-Ost (2321) Duesbergweg 10 - 14

11.01.22Hans-Jürgen Butt, MPI für Polymerforschung
Wetting on adaptive surfaces
16:15 Uhr s.t., Hörsaal CO2, Chemie - Nord-Ost (2321) Duesbergweg 10 - 14

18.01.22Marek Kowalski, HU Berlin/DESY
Multi-messanger Astronomy (TDEs)
16 Uhr c.t., Chemie - Nord-Ost (2321) Duesbergweg 10 - 14

25.01.22Mikhail Eremets, MPIC Mainz
Superconductivity
16 Uhr c.t., Hörsaal CO2 Chemie - Nord-Ost (2321) Duesbergweg 10 - 14

01.02.22Julie Grollier, CNRS/Thales Lab
Neuronale Netze / Festkörper
16 Uhr c.t., via Zoom

Koordination:

Prof. Dr. Sebastian Böser
Institut für Physik, ETAP
sboeser@uni-mainz.de

Prof. Dr. Frank Maas
Institut für Kernphysik
maas@uni-mainz.de

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