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Wormholes from Averaging over States
by Ben Freivogel, Dora Nikolakopoulou, Antonio F. Rotundo
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Antonio Rotundo |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2105.12771v2 (pdf) |
| Date accepted: | 2022-05-17 |
| Date submitted: | 2022-02-22 15:29 |
| Submitted by: | Rotundo, Antonio |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
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 $\langle A(t) A(0)\rangle$.
List of changes
- Added paragraph at the end of the introduction (page 3) to clarify that the wormhole we find is Lorentzian;
- Corrected discussion of thermodynamic limit (second paragraph at beginning of sec. 3.1, page 10);
- Added one bullet point about polynomial tails to the discussion (last paragraph of conclusion at page 30);
- Added a sentence about higher order terms in G below eq. 6.19;
- Explicit reference to eq. 4.1 (above eq. 4.2);
- Rearranged discussion of purity (page 7 from eq. 2.23 to the end of sec. 2.1);
- Replace g with h in eq. 3.19;
- Swapped left and right basis states in eq. 3.6, 4.15, and 4.22;
- Added Theta in eq. 4.14;
- Changed notation for partial transpose in eq. 4.14, and 3.7;
- Added a footnote at page 8 clarifying some aspects of the partial transpose.
Published as SciPost Phys. 14, 026 (2023)