Entanglement Islands from Replica Wormholes

During the last year, there was substantial progress in the understanding of the black hole information paradox from the perspective of Hawking's calculation. The novelty was the so-called "island formula", a new definition (within effective field theory) of the exact fine-grained entropy of a system coupled to gravity. In the context of black hole evaporation, the island formula indicates that, after the Page time, a large portion of the black hole interior is encoded in the early Hawking radiation. I would like to discuss the derivation of the island formula from a replica trick calculation, namely from the consideration of new wormhole saddles connecting the different replicas. The discussion will be hold within the context of JT gravity coupled to matter.

References:

- A modern conceptual review of the black hole information paradox and the island formula: https://arxiv.org/abs/2006.06872

- The island formula in JT gravity: https://arxiv.org/abs/1910.11077

- Replica wormholes in JT gravity: https://arxiv.org/abs/1911.12333 and https://arxiv.org/abs/1911.11977