Isaac Newton Institute for Mathematical Sciences

Quantum Gravity and Quantum Information

Black hole evaporation, unitarity, and final state projection

Author: Daniel Gottesman (Perimeter Institute)


What happens when a black hole evaporates? Does it leave behind anything more than a spray of Hawking radiation, and perhaps more importantly, how is the state of that radiation related to objects that fell into the black hole? In particular, is the overall behavior of the system unitary, or is information about the system's initial state irrevocably lost? I will give an overview of proposed resolutions to the black hole information-loss problem aimed towards those studying quantum information. I will then focus on a recent proposal by Horowitz and Maldacena to solve the problem by introducing a final state projection at the black hole singularity, and an objection to this solution by Preskill and myself.