Is there an information-loss problem for black holes?

TL;DR

The paper argues that black hole evaporation is a unitary process where thermal Hawking radiation results from decoherence, suggesting no fundamental information loss occurs, and explores the origins of black hole entropy.

Contribution

It presents a detailed comparison between black hole evaporation and cosmological decoherence, proposing a unitary evolution and a decoherence-based explanation for Hawking radiation.

Findings

Black hole evolution can be unitary with decoherence explaining thermal radiation.

Comparison with cosmology supports the decoherence approach.

Possible origins of black hole entropy include interactions with quasi-normal modes or background fields.

Abstract

Black holes emit thermal radiation (Hawking effect). If after black-hole evaporation nothing else were left, an arbitrary initial state would evolve into a thermal state (`information-loss problem'). Here it is argued that the whole evolution is unitary and that the thermal nature of Hawking radiation emerges solely through decoherence -- the irreversible interaction with further degrees of freedom. For this purpose a detailed comparison with an analogous case in cosmology (entropy of primordial fluctuations) is presented. Some remarks on the possible origin of black-hole entropy due to interaction with other degrees of freedom are added. This might concern the interaction with quasi-normal modes or with background fields in string theory.