# Calendar of Physics Talks Vienna

 A theoretical framework for CV-QKD
 Speaker: Bodo Kaiser (Universität München, DE) Abstract: Quantum key distribution (QKD) enables practical and secure-key generation to facilitate information-theoretical secure communication. A particular embodiment of QKD, continuous-variable QKD (CV-QKD), heavily influenced by telecommunication, encodes information by continuously modulating the quadratures of coherent light. The continuous-time preparation and measurement of coherent states is a constant source of contention between quantum physicists and communication engineers caused by the absence of a unified theoretical framework. The present thesis aims to resolve the seeming discrepancies between communication engineering and quantum physics by reviewing a practical implementation of a CV-QKD device. In the process, we find a self-contained description that the respective domain experts can agree on, allowing for a future transfer of methods between QKD and communication engineering. Date: Mon, 06.12.2021 Time: 10:00 Duration: 45 min Location: Hörsaal ATI /on-line; https://tuwien.zoom.us/j/96998466033?pwd=dUUzZ0xMdFBNcUo1bzZpWG1WTW4rUT09 Contact: Julian Leonard

 Why building a muon collider
 Speaker: Andrea Wulzer (EPFL Lausanne) Abstract: I will report on ongoing studies about the potential of such a very high energy muon collider to advance knowledge by direct searches for new particles and by precision measurements, and I will outline future directions of theoretical and experimental investigation towards a conclusive assessment of the muon collider physics case. These studies will offer guidance and motivation to the ongoing activity on the accelerator design in the context of the newly-formed International Muon Collider Collaboration. Date: Tue, 07.12.2021 Time: 14:00 Duration: 60 min Location: https://cern.zoom.us/j/69144452598?pwd=b3c3Z2NmV21GTWtyTjh4VGs1SklOUT09 Contact: Robert.schoefbeck@cern.ch

 Non-Lorentzian Supergravity in Ten Dimensions
 Speaker: Johannes Lahnsteiner (University of Groningen) Abstract: In this talk, I describe recent progress in understanding the background field dynamics of the non-relativistic string theory pioneered by Gomis and Ooguri. Building on earlier developments, I present a non-Lorentzian supergravity theory and explain how it constrains the dynamics of the background fields. Special attention will be given to the exotic geometric structures that arise in this theory. I will compare the results with those coming from beta function calculations. In the final part of my talk, I will comment on non-Lorentzian T-duality and an intriguing relation with double field theory. Date: Tue, 07.12.2021 Time: 14:00 Duration: 60 min Location: ZOOM: https://tuwien.zoom.us/j/97641048733?pwd=Q2JqOThkeXpUQy9ESit6R1NCZElkdz09 Password: uYTuX81c Contact: Romain Ruzziconi

 QED Initial State Radiation and $O(\alpha_s^3)$ Calculations for the Inclusive Determination of |V_{cb}|
 Speaker: Kay Schönwald (TTP, KIT - Karlsruhe) Abstract: In this talk I present recent work on sub-leading logarithmic corrections to the initial state radiation corrections to the process $e^+ e^- \to \gamma^*/Z^*$ and the calculation of $O(\alpha_s^3)$ corrections to the semileptonic $b \to c$ decay width. The first calculation is based on the method of massive operator matrix elements and allows to describe the initial state radiation of several processes at future electron-positron colliders at sub-permille accuracy. The second calculation is based on an expansion in the mass difference of charm and bottom quark. We show the good convergence properties of this series and compare the radiative corrections in different renormalization schemes for the heavy quark masses. Date: Tue, 07.12.2021 Time: 16:00 Duration: 60 min Location: ZOOM https://univienna.zoom.us/j/93427906843?pwd=YjhSejdUVW16QjVQYUh5TVNSNFNhQT09 Meeting ID: 934 2790 6843 Passcode: 073703 Contact: A. Hoang, M. Procura

 Non-degenerate Killing horizons in analytic vacuum spacetimes
 Speaker: Oliver Peterson (Uppsala University) Abstract: I will present a geometric characterization of all possible 4-dimensional real analytic vacuum spacetimes near non-degenerate Killing horizons. This result applies in particular to bifurcate horizons (e.g. black hole event horizons) and non-degenerate compact Cauchy horizons in real analytic vacuum spacetimes, since classical results of Hawking and Moncrief-Isenberg (and recent generalizations thereof) show that such horizons are non-degenerate Killing horizons. This is joint work with Klaus Kröncke. Date: Thu, 09.12.2021 Time: 14:00 Duration: 60 min Location: ZOOM https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 Contact: P. Chrusciel, D. Fajman

 Phenomenology of exotic scalars
 Speaker: Margherita Ghezzi (Tubingen University) Abstract: Doubly charged scalars often appear in Standard Model extensions motivated by mechanisms for neutrino mass generation. Within a general framework,the interactions of a doubly charged scalar with charged leptons allow for lepton flavour violation(LFV)therefore receiving significant bounds from low-energy LFV experiments.In the first part of this seminar I will briefly present the low-energy effective field theory for these models and review the present limits. Moreover,I will recall the current status of the LHC searches and present future perspectives for the HighLumi LHC phase and for future e+e- colliders. Finally, I will show how these different bounds from low- and high-energy physics need to be combined to get a coherent picture. The second part of the seminar will be devoted to other Beyond the Standard Model (BSM)scenarios,where singly and doubly charged bosonsmay appear as . . . Date: Thu, 09.12.2021 Time: 15:00 Duration: 60 min Location: ZOOM https://univienna.zoom.us/j/93427906843?pwd=YjhSejdUVW16QjVQYUh5TVNSNFNhQT09 Meeting ID: 934 2790 6843 Passcode: 073703 Contact: A. Hoang, M. Procura

 Supertranslations at timelike infinity
 Speaker: Debodirna Ghosh (Chennai) Abstract: We propose a definition of asymptotic flatness at timelike infinity in four spacetime dimensions. We present a detailed study of the asymptotic equations of motion and the action of supertranslations on asymptotic fields. We show that the Lee-Wald symplectic form Ω(g,δ1g,δ2g) does not get contributions from future timelike infinity with our boundary conditions. As a result, the future charges'' can be computed on any two-dimensional surface surrounding the sources at timelike infinity. We present expressions for supertranslation and Lorentz charges. Date: Thu, 09.12.2021 Time: 16:30 Duration: 60 min Location: https://tuwien.zoom.us/j/95482849369?pwd=SkU2WU5hMVJBQWsyVlFXRlRvQlIvdz09 Contact: Laura Donnay

 Cosmological constant problem: deflation during inflation
 Speaker: Benjamin Koch (TU Wien) Abstract: It is shown that the discrepancy between the Planck mass scale and the observed value of the cosmological constant can be largely attenuated, if those quantities are understood as a result of effective, and thus scale-dependent, couplings. We exemplify this mechanism for the early inflationary epoch of the universe by solving the corresponding effective gap equations, subject to an energy condition. Several non-trivial checks and extensions are discussed. A comparison of our results to the renormalization group flow, obtained within the asymptotic safety program reveals a stunning agreement. Date: Fri, 10.12.2021 Time: 10:00 Duration: 45 min Location: Hybridform and https://tuwien.zoom.us/j/99712909944?pwd=dmlybGJYa2tTUWdFQlNNRmJ6YWx3dz09 Contact: Hartmut Abele

 Searching Dark Matter with Cosmic Antiparticles
 Speaker: Martin Winkler (Stockholm University) Abstract: Weakly Interacting Massive Particles (WIMPs) have been the prime target of dark matter searches for decades.But only now,cosmic ray detectors are reaching the sensitivity to detect the energetic cascades of particles emitted by WIMP annihilation in the galactic halo.I will systematically reduce particle physics uncertainties which impact the dark matter detection by analysing a wide collection of accelerator data.This will allow me to perform an improved spectral search for dark matter and to scrutinize claims of a WIMP signal in the antiproton channel.Then I will turn to dark matter searches with cosmic ray antinuclei and to the tentative antihelium signal at AMS-02.I will describe a mechanism(within the Standard Model of particle physics)which can dramatically enhance the dark-matter induced antihelium flux. Very recent plans by the ALICE collaboration to test this mechanism at the LHC Date: Fri, 10.12.2021 Time: 16:00 Duration: 60 min Location: ZOOM https://univienna.zoom.us/j/93427906843?pwd=YjhSejdUVW16QjVQYUh5TVNSNFNhQT09 Meeting ID: 934 2790 6843 Passcode: 073703 Contact: A. Hoang, M. Procura