Black Hole Disappearance

Not much is known about what happens at the end of black hole evaporation. Pushing the semi-classical evolution well beyond its regime of validity suggests that the final Cauchy slice breaks into a piece that remains behind the event horizon, anchored to the point where the singularity meets the horizon, and a piece that detaches from the horizon to become a Cauchy slice for all future time evolution in slightly perturbed empty space. The evidence for this picture, however, remains scant. In fact, it is disputed by evaporating AdS black holes in two dimensions. I will offer a new scenario by analyzing evaporating black holes in a modified version of JT gravity that admits both empty AdS and black hole solutions. I will argue that the key to black hole disappearance is the emission of a baby universe that extracts the matter that formed the black hole, using the same mechanism for global symmetry violation in quantum gravity. This non-perturbative transition transforms the black hole into an excited state without a horizon that proceeds to disappear through reliable semi-classical evolution. This talk is based on work in progress with Shadi Ali Ahmad, Simon Lin, and Shoy Ouseph.