18098 1911.11977 10.1007/JHEP03(2022)205 205 205 Replica wormholes and the black hole interior Regular Article - Theoretical Physics 1 87 2022 3 30 2022 1 14 2022 3 10 2022 3 30 The Author(s) 2022 Open Access. This article is distributed under the terms of the Creative Commons Attribution License ( CC-BY 4.0 ), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited. 13130 2022 2022 3 3 Geoff Penington geoffp@berkeley.edu Stephen H. Shenker sshenker@stanford.edu Douglas Stanford salguod@stanford.edu Zhenbin Yang zhenbiny@stanford.edu grid.168010.e 0000000419368956 Stanford Institute for Theoretical Physics Stanford University Stanford CA 94305 USA Abstract Recent work has shown how to obtain the Page curve of an evaporating black hole from holographic computations of entanglement entropy. We show how these computations can be justified using the replica trick, from geometries with a spacetime wormhole connecting the different replicas. In a simple model, we study the Page transition in detail by summing replica geometries with different topologies. We compute related quantities in less detail in more complicated models, including JT gravity coupled to conformal matter and the SYK model. Separately, we give a direct gravitational argument for entanglement wedge reconstruction using an explicit formula known as the Petz map; again, a spacetime wormhole plays an important role. We discuss an interpretation of the wormhole geometries as part of some ensemble average implicit in the gravity description. Keywords 2D Gravity AdS-CFT Correspondence Black Holes Gauge-Gravity Correspondence ArXiv ePrint: 1911.11977