Schedule May 26, 2022
The Hilbert space of quantum gravity with replica wormholes
Henry Maxfield, Stanford
Cite as: doi:10.26081/K6434N

Black holes highlight a problem with our understanding of quantum gravity: using a semiclassical approximation, they appear to have too many internal states. New light has been shed recently by “replica wormholes”, indicating that non-perturbative semiclassical effects can resolve this problem. But this result is somewhat indirect, so the fate of the extra apparent states remains mysterious. I’ll discuss replica wormholes more directly from the perspective of the Hilbert space of black holes, as a modification to the inner product. I give three applications: (1) a simple qubit model of a black hole with unitary evaporation, a Page curve and a smooth horizon, (2) a counting of black hole states which makes the fate of the extra states manifest, and (3) an interpretation of replica wormholes as arising from an extended gauging of diffeomorphisms.

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