Observation of incipient black holes and the information loss problem

Abstract

We study the formation of black holes by spherical domain wall collapse as seen by an asymptotic observer, using the functional Schr\odinger formalism. To explore what signals such observers will see, we study radiation of a scalar quantum field in the collapsing domain wall background. The total energy flux radiated diverges when backreaction of the radiation on the collapsing wall is ignored, and the domain wall is seen by the asymptotic observer to evaporate by nonthermal ``pre-Hawking radiation'' during the collapse process. Evaporation by pre-Hawking radiation implies that an asymptotic observer can never lose objects down a black hole. Together with the nonthermal nature of the radiation, this may resolve the black hole information loss problem.