19 Apr 2021
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., usually Staudingerweg 7, Minkowskiraum |
Vincent Roy, Universität Mainz | |
The Story of the Mainz Neutrino Mass Experiment | |
at Zoom for now | |
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SFB/TR49/SFB TRR 173 Spin+X-Kolloquium/TopDyn - Seminar experimentelle Physik der kondensierten Materie
SFB/TR49 - Prof. Dr. Elmers 16:00 Uhr s.t., None |
Andrii Chumak, University of Vienna, Austria | |
Nano-Magnonics: From Room to Cryogenic Temperatures | |
at Zoom | |
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aktuell
20 Apr 2021
Theorie-Palaver
Institut für Physik 14:30 Uhr s.t., MITP seminar room |
Xiaofeng Xu, Bern University | |
Canonical Feynman integrals are of great interest in the study of scattering amplitudes at the multi-loop level. We propose to construct d log-form integrals of the hypergeometric type, treat them as a representation of Feynman integrals, and project them into master integrals using intersection theory. This provides a constructive way to build canonical master integrals whose differential equations can be solved easily. We use our method to investigate both the maximally cut integrals and the uncut ones at one and two loops, and demonstrate its applicability in problems with multiple scales. | |
at Zoom | |
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Physikalisches Kolloquium
Institut für Kernphysik, Remote Seminar 16:15 Uhr s.t., None |
Mehran Kardar, Massachusetts Institute of Technology, Cambridge, USA | |
Affinity maturation (AM) is the process through which the immune system evolves antibodies (Abs) which efficiently bind to antigens (Ags), e.g. to spikes on the surface of a virus. This process involves competition between B-cells: those that ingest more Ags receive signals (from T helper cells) to replicate and mutate for another round of competition. Modeling this process, we find that the affinity of the resulting Abs is a non-monotonic function of the target (e.g. viral spike) density, with the strongest binding at an intermediate density (set by the two-arm structure of the antibody). We argue that, to evade the immune system, most viruses evolve high spike densities (SDs). An exception is HIV whose SD is two orders of magnitude lower than other viruses. However, HIV also interferes with AM by depleting T helper cells, a key component of Ab evolution. We find that T helper cell depletion results in high affinity antibodies when SD is high, but not if SD is low. This special feature of HIV infection may have led to the evolution of a low SD to avoid potent immune responses early on in infection. Our modeling also provides guides for design of vaccination strategies against rapidly mutating viruses. | |
at Zoom | |
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zukünftige Termine
21 Apr 2021
GRK 2516 Soft Matter Seminar
Uni Mainz 10:30 Uhr s.t., None |
Angelika Kühnle, Bielefeld University | |
TBA | |
at Zoom | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t., None |
Chiara Ciccarelli, University of Cambridge | |
Spin transport in a conventional superconductor | |
at Zoom and SPICE YouTube Channel | |
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22 Apr 2021
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., None |
Prof. Dr. Konrad Lehnert, JILA, University of Colorado, Boulder, USA | |
Can emerging quantum information technologies, in some way, improve or enhance searches for fundamental physical phenomena? Indeed, the use of optical squeezing in gravitational wave observatories is a beautiful example that they can. In addition to this one prominent example, the search for dark matter may offer several other near-term experiments that can, and perhaps must, use enhanced quantum sensing methods. In particular detail, I’ll discuss the case of searching for a hypothetical dark matter particle known as the axion and accelerating the search using quantum squeezing approaches. | |
at Zoom | |
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