Calendar of Physics Talks Vienna

Electromagnetic edge modes and black hole entropy
Speaker:Glenn Barnich (Université Libre de Bruxelles)
Abstract:Im Rahmen des Joint Theory Seminars: In linearised gravity, the Schwarzschild solution and its mass are related to unphysical degrees of freedom rather than physical gravitons. This motivates the study of the analog problem in electromagnetism, where the role of the black hole is played by the Coulomb solution, while mass corresponds to electric charge. It is shown that (i) when all polarisations of the photon are quantised in an indefinite metric Hilbert space, the quantum state corresponding to the classical Coulomb solution is a coherent state of longitudinal and temporal photons, and (ii) the edge modes of a charged vacuum capacitor give a contribution to the partition function that is proportional to the area and allow for a microscopic derivation of the contribution to the partition function obtained by applying the Gibbons-Hawking approach to the charged capacitor.
Date: Tue, 16.10.2018
Time: 13:45
Duration: 60 min
Location:TU Wien, GETREIDEMARKT 9, Maschinenbaugebäude, 1. Stock, HS Kleiner Schiffbau
Contact:S. Fredenhagen, D. Grumiller

Light at the Horizon: Observation of Stimulated Hawking Radiation in Optics
Speaker:Ulf Leonhardt (Weizmann Institute of Science, Israel)
Abstract:Hawking radiation has been one of the intellectually most influential predictions of theoretical physics, connecting general relativity with quantum mechanics and thermodynamics, but it has never been fully observed yet, even in laboratory analogues, despite admirable experimental progress made. Here we report on clear, non-ambiguous measurements of stimulated Hawking radiation in nonlinear fiber optics. Our experiment shows the surprising robustness of the Hawking effect in optics and may finally clear the path towards a full quantum demonstration.
Date: Tue, 16.10.2018
Time: 14:30
Duration: 40 min
Location:TU Wien, Atominstitut, Seminarraum
Contact:Arno Rauschenbeutel

Recent developments in tools for Beyond the Standard Model phenomenology studies
Speaker:Federico Ambrogi (Univ. Wien)
Abstract:Im Rahmen des Teilchenphysikseminars: The search for Beyond the Standard Model (BSM) physics is one of the main challenges for both experimentalists and theorists in particle physics. Astrophysical observations show that around 25% of the energy content of the universe includes a form of particle dark matter (DM), that cannot be explained by the Standard Model. In this talk I will present the recent developments in three tools commonly used for the study of the phenomenology of BSM physics: MadAnalysis 5, SModelS and MadDM. These packages provide a direct connection between the data collected by e.g. the detectors at the LHC or by DM indirect detection experiments and the theoretical predictions of new physics models, allowing to efficiently constrain their large parameter space.
Date: Tue, 16.10.2018
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, H. Neufeld, S. Plätzer, M. Procura

Wave equations with initial data on compact Cauchy horizons
Speaker:Oliver Petersen (Universität Hamburg)
Abstract:I will present a new existence and uniqueness result for wave equations with initial data on compact Cauchy horizons. As counter examples show, it is necessary to assume that the surface gravity of the Cauchy horizon can be normalised to a non-zero constant. This generalizes classical results proven under the assumption of either analyticity or symmetry of the spacetime or closedness of the generators. In particular, the result is useful in understanding the geometry of vacuum spacetimes with a compact Cauchy horizon. This problem is closely related to the strong cosmic censorship conjecture.
Date: Thu, 18.10.2018
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel, D. Fajman

Classical de Sitter solutions and the swampland
Speaker:David Andriot (CERN)
Abstract:I will first give a brief overview of the difficulties in getting controlled de Sitter vacua from string theory. This motivated the recent proposal of a swampland criterion forbidding de Sitter solutions. I will discuss consequences and a possible refinement of this criterion. I will finally present the most recent constraints on classical de Sitter solutions in 10d type II supergravities.
Date: Thu, 18.10.2018
Time: 16:00
Duration: 60 min
Location:Sem.R. DB gelb 10 - Freihaus, TU Wien
Contact:Timm Wrase