PIRSA:20050018

Black hole information, spacetime wormholes and baby universes

Maxfield, H. (2020). Black hole information, spacetime wormholes and baby universes. Perimeter Institute. https://pirsa.org/20050018

Maxfield, Henry. Black hole information, spacetime wormholes and baby universes. Perimeter Institute, May. 14, 2020, https://pirsa.org/20050018 

          @misc{ pirsa_PIRSA:20050018,
            doi = {10.48660/20050018},
            url = {https://pirsa.org/20050018},
            author = {Maxfield, Henry},
            keywords = {Quantum Fields and Strings},
            language = {en},
            title = {Black hole information, spacetime wormholes and baby universes},
            publisher = {Perimeter Institute},
            year = {2020},
            month = {may},
            note = {PIRSA:20050018 see, \url{https://pirsa.org}}
          }

Henry Maxfield

University of California, Santa Barbara

Talk number
PIRSA:20050018
Collection
Talk Type
Subject
Abstract

Hawking famously observed that the formation and evaporation of black holes appears to violate the unitary evolution of quantum mechanics. Nonetheless, it has been recently discovered that a signature of unitarity, namely the "Page curve" describing the evolution of entropy, can be recovered from semiclassical gravity. This result relies on "replica wormholes" appearing in the gravitational path integral, which are examples of spacetime wormholes studied more than 30 years ago and related to interactions with closed "baby" universes. I will discuss the connection between these new and old ideas and the consequences for the black hole information problem. A central lesson is that a Hilbert space in quantum gravity can be dramatically modified by nonperturbative topology-changing processes.