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Calendar of Physics Talks Vienna
| Digging traversable wormholes |
| Speaker: | Roberto Emparan (Barcelona U.) |
| Abstract: | In recent years there have appeared several constructions of traversable wormholes, in four and other dimensions, which only involve physically acceptable, controllable ingredients. They connect in deep ways many aspects of gravity, quantum field theory, and quantum information. I will discuss several features of these constructions, with a focus on traversability, connectivity between multiple mouths, and the (im)possibility of time travel. |
| Date: | Tue, 27.04.2021 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | https://moodle.univie.ac.at/mod/bigbluebuttonbn/guestlink.php?gid=x8o6ILSKJuC9 |
| Contact: | Céline Zwikel |
| Covariant Weyl calculus with application to geometrical optics in relativity |
| Speaker: | Jérémie Joudioux (AEI Golm) |
| Abstract: | Geometrical optics consists of approximating the evolution of an electromagnetic wave,solution to Maxwell’s equations,by ray equations. In the limit of infinite frequencies, the rays have the usual semi-classical interpretation of being the paths of photons,null geodesics. At high but finite frequencies, corrections to these rays are expected. For light propagating in a medium,these corrections have been observed. In quantum mechanics,corrections in the context of adiabatic perturbations theory are well-studied.Wigner functions belong to the tools commonly used to capture them.In this talk, I will present a covariant version of Wigner-Weyl calculus which can,at least formally, be used in relativity.Corrections to geometrical optics can then be calculated,and one recovers results previously obtained by Oancea,et al., and Andersson, et al.. The effective ray equations can be recast as ... |
| Date: | Thu, 29.04.2021 |
| Time: | 15:00 |
| Duration: | 60 min |
| Location: | ZOOM-meeting: https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 |
| Contact: | Piotr Chrusciel, David Fajman |
| The imaginary part of the heavy-quark potential from real-time Yang-Mills dynamics |
| Speaker: | Kirill Boguslavski (TU Wien) |
| Abstract: | The suppression of heavy quark-antiquark bound states like bottomonium in heavy-ion collisions is an important observable for the quark-gluon plasma state. Theoretically, this can be quantified by the heavy-quark potential. In this talk, I will present our results on extracting its imaginary part using classical-statistical simulations of real-time Yang-Mills dynamics in classical thermal equilibrium. We compare our results to perturbation theory calculations in hard thermal loop formalisms. We find that, when considered as a function of m_D r, where m_D is the soft scale, the imaginary part of the heavy-quark potential becomes independent of the lattice spacing at sufficiently small r and agrees well with perturbative results. We finally relate the short-distance behavior of the potential to the heavy-quark transport coefficient κ, providing an estimate of the latter. |
| Date: | Thu, 29.04.2021 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | https://tuwien.zoom.us/j/95482849369?pwd=SkU2WU5hMVJBQWsyVlFXRlRvQlIvdz09 |
| Contact: | Laura Donnay, Anton Rebhan |
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