An important question about black holes is to what extent a typical pure state differs from the ensemble average. We show that this question can be answered within semi-classical gravity. We focus on the quantum deviation, which measures the fluctuations in the expectation value of an operator in an ensemble of pure states. For a large class of ensembles and observables, these fluctuations are calculated by a correlation function in the eternal black hole background, which can be reliably calculated within semi-classical gravity. This implements the idea of [arXiv:2002.02971] that wormholes can arise from averages over states rather than theories. As an application, we calculate the size of the long-time correlation function $\langle A(t) A(0)\rangle$.
Cited by 3
Banerjee et al., Geometric quantum discord signals non-factorization
J. High Energ. Phys. 2023, 104 (2023) [Crossref]
Chandra et al., Coarse graining pure states in AdS/CFT
J. High Energ. Phys. 2023, 30 (2023) [Crossref]
de Boer et al., Worldsheet traversable wormholes
J. High Energ. Phys. 2023, 141 (2023) [Crossref]
Authors / Affiliations: mappings to Contributors and OrganizationsSee all Organizations.
- 1 2 Ben Freivogel,
- 1 Dora Nikolakopoulou,
- 1 Antonio Rotundo
- 1 Institute of Physics, University of Amsterdam [IoP, UvA]
- 2 Universiteit van Amsterdam / University of Amsterdam [UvA]