MCTP HET BROWN BAG SEMINAR
Black Holes, Fuzzballs and Firewalls
The information paradox and the infall problem have been long-standing puzzles in the understanding of black holes. The idea of free infall is in considerable tension with unitarity of the evaporation process and recent developments have made this tension sharp. In the first part of my talk I will address the information question and argue that unitarty requires every quantum of radiation leaving the black hole to carry information about the initial state. Unitary evaporation is thus inconsistent with an information-free horizon at every step of the evaporation process. This immediately raises the question of what the required horizon-scale structure is? I will show an explicit construction of near-extremal black hole microstates which put flesh and branes on the fuzzball proposal and may realize firewalls in string theory. Finally I will address the question of what happens to an observer falling into a fuzzball.