Gravity seminar - Romain Ruzziconi Seminar

Abstract:

In this talk, I will discuss some generic boundary conditions in asymptotically locally (A)dS spacetimes that yield some flux through the conformal boundary. After a holographic renormalization procedure to remove the divergences arising at the level of the symplectic structure, the asymptotic symmetries and the charge algebra associated with these leaky boundary conditions will be presented. We will see that the charge algebra generically involves a field-dependent 2-cocycle in odd spacetime dimensions. In particular, when the general framework is restricted to three-dimensional asymptotically AdS spacetimes with Dirichlet boundary conditions, I will show that the 2-cocycle consistently reduces to the Brown Henneaux central extension. Then I will provide a specific example of leaky boundary conditions that leads to BMS-like symmetries in presence of non-vanishing cosmological constant. In the flat limit, I will show that these symmetries and the associated phase space reduce to those of Generalized BMS in asymptotically flat spacetimes. This talk is based on 2004.10769 and 2011.02002