2020/11/18 by Kanato Goto, Thomas Hartman, Amirhossein Tajdini · 1 citation
Physics and Astronomy · #Black Holes and Theoretical Physics #Black hole (networking) #Cosmology and Gravitation Theories #Euclidean geometry #Extremal black hole #Gravitation #Massive gravity #Noncommutative and Quantum Gravity Theories #Replica #Replica trick #Wormhole #hep-th
paper · pdf · doi:10.1007/jhep04(2021)289
65 pages, 19 figures
arxiv created 2020/11/18 · openalex created_date 2020/11/23 · openalex publication_date 2021/04/01 · arxiv updated 2021/05/19 · openalex updated_date 2026/08/06
A bstract Quantum extremal islands reproduce the unitary Page curve of an evaporating black hole. This has been derived by including replica wormholes in the gravitational path integral, but for the transient, evaporating black holes most relevant to Hawking’s paradox, these wormholes have not been analyzed in any detail. In this paper we study replica wormholes for black holes formed by gravitational collapse in Jackiw-Teitelboim gravity, and confirm that they lead to the island rule for the entropy. The main technical challenge is that replica wormholes rely on a Euclidean path integral, while the quantum extremal islands of an evaporating black hole exist only in Lorentzian signature. Furthermore, the Euclidean equations for the Schwarzian mode are non-local, so it is unclear how to connect to the local, Lorentzian dynamics of an evaporating black hole. We address these issues with Schwinger-Keldysh techniques and show how the non-local equations reduce to the local ‘boundary particle’ description in special cases.