Physikalisches Kolloquium

Programm für das Wintersemester 2020/2021

Tuesdays, 16 Uhr c.t.

Institut für Kernphysik, Remote Seminar

live at Zoom

keine vergangenen Seminare

zukünftige Termine
17.11.20Dieter Ries, University of Mainz
Ultracold Neutrons (UCN) provide a unique tool for fundamental neutron research with long observation times. Once produced e.g. in one of the UCN sources at the TRIGA Mainz research reactor, they can be confined by suitable materials, gravity or strong magnetic fields ultimately only limited by the beta decay lifetime of the free neutron. The τSPECT experiment, which is close to being fully commissioned on-site at JGU, aims for a precision determination of the neutron lifetime, which is currently under scrutiny because different measurement techniques yield incompatible results. Another precision measurement with UCN is the search for a non-vanishing electric dipole moment of the neutron, which would violate CP symmetry. Together with the international nEDM collaboration we have recently published a new upper limit on the neutron EDM and are currently commissioning the next generation experiment "n2EDM" at PSI, Switzerland, which aims to push down the limit by an order of magnitude in the coming years. The current state of and results from the τSPECT, nEDM and n2EDM experiment will be presented.
16:15 Uhr s.t., at Zoom

24.11.20Bert Koopmans, Eindhoven University of Technology, The Netherlands
to be announced
16:15 Uhr s.t., at Zoom

01.12.20Eli Zeldov, Department of Condensed Matter Physics, Weizmann Institute of Science, Israel
Energy dissipation is a fundamental process governing the dynamics of classical and quantum systems. Despite its vital importance, direct imaging and microscopy of dissipation in quantum systems is currently mostly inaccessible because the existing thermal imaging methods lack the necessary sensitivity and are unsuitable for low temperature operation. We developed a scanning nanoSQUID that resides at the apex of a sharp pipette acting simultaneously as nanomagnetometer with single spin sensitivity and as nanothermometer providing cryogenic thermal imaging with four orders of magnitude improved thermal sensitivity of below 1 µK [1]. The non-contact non-invasive thermometry enables direct visualization and control of the minute heat generated by electrons scattering off a single atomic defect in graphene [2]. By further combining the scanning nanothermometry with simultaneous scanning gate microscopy we demonstrate independent imaging of work and dissipation and reveal the microscopic mechanisms that conceal the true topological protection in the quantum Hall state in graphene [3]. [1] D. Halbertal, J. Cuppens, M. Ben Shalom, L. Embon, N. Shadmi, Y. Anahory, H. R. Naren, J. Sarkar, A. Uri, Y. Ronen, Y. Myasoedov, L. S. Levitov, E. Joselevich, A. K. Geim, and E. Zeldov, Nature 539, 407 (2016). [2] D. Halbertal, M. Ben Shalom, A. Uri, K. Bagani, A.Y. Meltzer, I. Marcus, Y. Myasoedov, J. Birkbeck, L.S. Levitov, A.K. Geim, and E. Zeldov, Science 358, 1303 (2017). [3] A. Marguerite, J. Birkbeck, A. Aharon-Steinberg, D. Halbertal, K. Bagani, I. Marcus, Y. Myasoedov, A.K. Geim, D.J. Perello, and E. Zeldov, Nature 575, 628 (2019).
16:15 Uhr s.t., at Zoom

08.12.20Sherry Suyu, TU München
to be announced
16:15 Uhr s.t., at Zoom

15.12.20Baha Balantekin, University of Wisconsin-Madison, USA
to be announced
16:15 Uhr s.t., at Zoom

12.01.21Zheng-Tian Lu, University of Science and Technology of China
to be announced
16:15 Uhr s.t., at Zoom

19.01.21Bernadett Weinzierl, University of Vienna, Austria
to be announced
16:15 Uhr s.t., at Zoom

26.01.21Viola Priseman, Max-Planck-Institution , Göttingen, Germany
to be announced
16:15 Uhr s.t., at Zoom

02.02.21Andy Brown, ECMWF, Reading, Great Britain
to be announced
16:15 Uhr s.t., at Zoom

09.02.21Michael Feindt, University of Karlsruhe
to be announced
16:15 Uhr s.t., at Zoom

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Koordination:

Prof. Dr. Matthias Schott
Institut für Physik, ETAP
schottm@uni-mainz.de

Prof. Dr. Achim Denig
Institut für Kernphysik
denig@uni-mainz.de