Conservative solutions to the black hole information problem

TL;DR

This paper reviews various approaches to resolving the black hole information paradox, emphasizing conservative solutions that preserve unitarity by eliminating singularities, including considerations within the AdS/CFT framework.

Contribution

It classifies the options for resolving the black hole information problem into radical and conservative categories, advocating for singularity elimination as a key conservative solution.

Findings

Restoring unitarity depends on eliminating singularities.

Conservative solutions do not require large deviations from semi-classical physics.

Singularity elimination should also apply within AdS/CFT correspondence.

Abstract

We review the different options for resolution of the black hole loss of information problem. We classify them first into radical options, which require a quantum theory of gravity which has large deviations from semi-classical physics on macroscopic scales, such as non-locality or endowing horizons with special properties not seen in the semi-classical approximation, and conservative options, which do not need such help. Among the conservative options, we argue that restoring unitary evolution relies on elimination of singularities. We argue that this should hold also in the AdS/CFT correspondence.