IQI Weekly Seminar

Abstract: The black hole information paradox is the supposed contradiction between information loss in perturbative semiclassical gravity and the unitarity of quantum mechanics. I argue that in fact the semiclassical gravity description secretly knows that information is preserved, when looked at through the lens of modern quantum gravity, specifically the Ryu-Takayanagi formula and entanglement wedge reconstruction. At exactly the Page time, when information is meant to start leaking out of the black hole, there is a phase transition in the RT surface. This phase transition exactly predicts the Hayden-Preskill decoding criterion, which was previously only conjectured based on unitarity and the chaotic black hole dynamics. It also gives a derivation of the ER=EPR resolution of the firewall paradox. A combination of holographic and information-theoretic arguments show that the interior of the black hole is encoded in the Hawking radiation with exaclty the same state dependence that would be expected from random unitary toy models.