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Calendar of Physics Talks Vienna
| Speaker: | Claudia de Rham (Imperial College London) |
| Abstract: | In standard effective field theories, the notion of causality is intrinsically linked with that of subluminality and with a set of positivity constraints to be imposed on the low-energy scattering amplitudes. I will highlight how the presence of gravity leads to a more subtle relation between causality, (sub)luminality and positivity bounds. These considerations are relevant for putting constraints on cosmological and gravitational effective field theories and I will provide explicit criteria to be satisfied so as to ensure causality and a standard high energy completion in gravitational effective field theories. |
| Date: | Tue, 25.05.2021 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | https://tuwien.zoom.us/j/95482849369?pwd=SkU2WU5hMVJBQWsyVlFXRlRvQlIvdz09 |
| Contact: | Céline Zwikel |
| The dynamics and statics of floating bodies (joint work with B.Schmidt) |
| Speaker: | Robert Beig (Univ. Vienna) |
| Abstract: | Bodies floating in still water are subject to the laws of rigid body mechanics combined with Archimedes' principle. We write down the equations governing their dynamics. These equations take the form of a Hamiltonian system similar to, but richer in structure than, the well-known heavy top. The sometimes surprising equilibrium configurations of floating bodies have attracted interest from the times of Archimedes up until today. The stability properties of equilibria have essentially been known since the 18th century and extensively used in naval architecture and by glaciologists studying icebergs. We give a precise statement of these stability criteria and an elementary proof of nonlinear stability under time evolution. |
| Date: | Thu, 27.05.2021 |
| Time: | 15:00 |
| Duration: | 30 min |
| Location: | https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 |
| Contact: | Piotr Chrusciel, David Fajman |
| An entanglement perspective on quantum many-body systems |
| Speaker: | Norbert Schuch (Universität Wien) |
| Abstract: | Quantum many-body systems exhibit a wide range of exciting and unconventional phenomena, such as order outside the conventional framework of symmetry breaking ("topological order") which is accompanied by excitations with exotic properties ("anyons"), and the ability to store and process quantum information. All these phenomena are deeply rooted in the complex global quantum entanglement present in these systems. In my talk, I will explain how Quantum Information Theory, and in particular the theory of entanglement, provides us with a comprehensive perspective on these systems, which reconciles their global entanglement with the locality inherent to the physical laws, using the language of tensor networks. I will discuss how this allows us to obtain a full picture of how symmetries and entanglement interplay, and how it provides us both with a mathematical framework to analytically study |
| Date: | Fri, 28.05.2021 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | on-line |
| Contact: | Marcus Huber |
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