The island beyond the end of the world

by Marco Meineri (Universite de Geneve (CH))

Monday 28 Feb 2022, 13:30 → 15:00 Europe/Zurich

zoom only (CERN)

Large black holes in anti-de Sitter space have positive specific heat and do not evaporate. In order to mimic the behavior of evaporating black holes, one may couple the system to an external bath. I will discuss a class of models dual to interface CFTs. The bulk solution is characterized by a thin brane separating two AdS regions. These systems may be interpreted in a double holographic way, where one integrates out the bath and ends up with a lower-dimensional gravitational braneworld dual to the interface degrees of freedom. Focusing on a three dimensional bulk, I will describe geodesics in this space, and use them to prove that the entropy of Hawking radiation in the braneworld is obtained by extremizing the generalized entropy. The detailed match works for quantities not fixed by symmetry, and independent of the UV cutoff. The more familiar setup of the end-of-the-world brane can be obtained as a limit: this allows to derive Takayanagi's rule to compute entanglement entropy in BCFT as a consequence of the standard AdS/CFT dictionary.