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Black Hole Airy Tail

Stefano Antonini ^*, Luca V. Iliesiu ^†, Pratik Rath ^‡, and Patrick Tran ^§

Leinweber Institute for Theoretical Physics and Department of Physics, University of California, Berkeley, California 94720, USA

^*Contact author: santonini@berkeley.edu
^†Contact author: liliesiu@berkeley.edu
^‡Contact author: pratik_rath@berkeley.edu
^§Contact author: patrick.tran@berkeley.edu

Phys. Rev. Lett. 135, 191501 – Published 6 November, 2025

DOI: https://doi.org/10.1103/ft96-b212

Abstract

In Jackiw-Teitelboim (JT) gravity, which is dual to a random matrix ensemble, the annealed entropy differs from the quenched entropy at low temperatures and goes negative. However, computing the quenched entropy in JT gravity requires a replica limit that is poorly understood. To circumvent this, we define an intermediate quantity called the semiquenched entropy, which has the positivity properties of the quenched entropy, while requiring a much simpler replica trick. We compute this in JT gravity in different regimes using (i) a bulk calculation involving wormholes corresponding to the Airy limit of the dual matrix integral and (ii) a boundary calculation involving one-eigenvalue instanton saddles proposed by Hernández-Cuenca, demonstrating consistency between these two calculations in their common regime of validity. We also clarify why similar one-eigenvalue instanton saddles cannot be used to compute the quenched entropy due to a breakdown of the saddle-point approximation for the one-eigenvalue instanton in the replica limit. Our results show how to use the gravitational path integral to prove that black holes in JT gravity have isolated ground states and to study their properties.

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References (33)

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Phys. Rev. Lett. 135, 191501– Published 6 November, 2025

Vol. 135, Iss. 19 — 7 November 2025

Received 25 July 2025
Revised 8 September 2025
Accepted 22 October 2025

DOI: https://doi.org/10.1103/ft96-b212

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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Black Hole Airy Tail

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