Theory HEP Seminar

Signatures of unitarity in semiclassical black hole evaporation

Henry Maxfield

UC Santa Barbara

Hawking famously demonstrated that semiclassical gravity is in tension with the unitary evolution of quantum mechanics when black holes evaporate. I’ll describe a semiclassical calculation that nonetheless reproduces signatures of unitarity, namely the “Page curve” of entropy evolution and the Hayden-Preskill protocol. The new input, coming from recent advances in AdS/CFT, involves a “quantum extremal surface”, a stationary surface for Bekenstein’s generalised entropy. For exact calculations, I introduce a solvable model of Jackiw-Teitelboim gravity and conformal matter, coupled to an auxiliary system to allow the black hole to evaporate. I will conclude by commenting and speculating on the implications for the information paradox.