Status | Confirmed |
Seminar Series | IPHT-MAT |
Subjects | hep-th |
Date | Wednesday 19 February 2020 |
Time | 14:15 |
Institute | IPHT |
Seminar Room | Salle Claude Itzykson, Bât. 774 |
Speaker's Last Name | Geoffrey Compère |
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Speaker's Institution | Université Libre de Bruxelles |
Title | Some physics behind supertranslations and superrotations |
Abstract | I will first provide a bird-eye view upon the infrared structure of gravity. I will shortly describe the relationship between BMS symmetry, soft theorems and memory effects at leading and subleading orders in the large radius expansion, while emphasizing the specificities of super-Lorentz symmetries. Secondly, I will present a no-go result on the soft hair conjecture: supertranslations induced by matter creating and falling inside black holes do not affect Hawking radiation, though they do affect scattering amplitudes. I will start by proving that Unruh radiation is unaffected by supertranslations induced by a shockwave and then show that Hawking radiation is mathematically related to this system, as a consequence of the principle of equivalence. Third, I will explain how BMS symmetry is associated to flux-balance laws that provide constraints upon the motion of binary compact mergers. Finally, I will present the extension of the BMS group to asymptotically de Sitter spacetimes. |
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