The entropy of bulk quantum fields and the entanglement wedge of an evaporating black hole

Ahmed Almheiri, Netta Engelhardt, Donald Marolf, Henry Maxfield

Research output: Contribution to journalArticlepeer-review


Bulk quantum fields are often said to contribute to the generalized entropy A4GN+Sbulk only at O(1). Nonetheless, in the context of evaporating black holes, O(1/GN) gradients in Sbulk can arise due to large boosts, introducing a quantum extremal surface far from any classical extremal surface. We examine the effect of such bulk quantum effects on quantum extremal surfaces (QESs) and the resulting entanglement wedge in a simple two-boundary 2d bulk system defined by Jackiw-Teitelboim gravity coupled to a 1+1 CFT. Turning on a coupling between one boundary and a further external auxiliary system which functions as a heat sink allows a two-sided otherwise-eternal black hole to evaporate on one side. We find the generalized entropy of the QES to behave as expected from general considerations of unitarity, and in particular that ingoing information disappears from the entanglement wedge after a scambling time β2πlogΔS+O(1) in accord with expectations for holographic implementations of the Hayden-Preskill protocol. We also find an interesting QES phase transition at what one might call the Page time for our process.

Original languageEnglish (US)
Article number63
JournalJournal of High Energy Physics
Issue number12
StatePublished - Dec 1 2019


  • 2D Gravity
  • AdS-CFT Correspondence
  • Black Holes in String Theory
  • Gauge- gravity correspondence

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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