Speaker
Henry Maxfield
Description
Abstract:
It has long been argued that black holes can be modeled as unitary quantum systems with density of states given by the Bekenstein-Hawking formula. It now seems that this idea is realised within semiclassical gravity, without using details of the UV completion or assuming duality. I will describe this in an asymptotically flat setting using Lorentz-signature gravitational path integrals, concentrating on the predictions for observables. However, for this semiclassical picture to be coherent, we are forced to conclude that there are superselection sectors for asymptotic observers. These sectors are associated with the states of baby universes, which appear when we consider the Hilbert space interpretation of replica wormholes.
