| Saturday 4 May 2024 | |
| Events for day: Tuesday 06 July 2021 |
| 13:30 - 14:30 Weekly Seminar HEPCo Group On Diff(S2) and asymptotically spatially flat FLRW School PHYSICS Abstract: In this talk we will explore deformations and extensions of the algebra of vector fields on the sphere. Our main motivation comes from the fact that (some) non-central extensions of this algebra correspond to the asymptotic algebras of asymptotically flat and asymptotically spatially flat FLRW spacetimes at future null infinity. The former are well-known, while the latter have been recently proposed and will be discussed in more detail. This talk is based on the following papers: 2011.01960, 2102.02234 (asymptotically flat FLRW spacetimes) and 2105.13375 (deformations and extensions of Diff(S^2)). ... 17:00 - 18:00 IPM Holography virtual seminar Half-wormholes and factorization problem School PARTICLES AND ACCELERATORS Abstract: I will discuss the factorization problem in an SYK model with one time point. Working in a collective field description, one can derive an identity: the square of the partition function with fixed couplings is well approximated by a wormhole saddle plus a half-wormhole saddle. It explains factorization of decoupled systems. I will develop a perturbative expansion around the half-wormhole saddle. This expansion truncates at a finite order and gives the exact answer. The last term in the perturbative expansion turns out to coincide with the wormhole contribution. In this sense the wormhole saddle in this model does not need to be adde ... 17:30 - 19:30 Number Theory Webinar On Drinfeld Modular Forms of Higher Rank and Quasi-Periodic Functions School MATHEMATICS In 1980s, David Goss introduced Drinfeld modular forms in the rank two case and revealed several similarities between them and the classical modular forms as well as giving a recipe for how to construct them for the higher rank setting. Later on their higher rank generalization was studied extensively by Basson, Breuer, Gekeler and Pink. In this talk, we introduce a special function on the Drinfeld period domain in the higher rank setting which also generalizes the false Eisenstein series of Gekeler. We also introduce its functional equation, its relation with quasi-periodic functions of a Drinfeld module and the transcendence of its values a ... |