Information-preserving black holes still do not preserve baryon number and other effective global quantum numbers

TL;DR

This paper argues that even if black holes preserve information in a quantum sense, they still violate baryon number and other approximate or anomalous global quantum numbers, challenging claims of resolving the information paradox.

Contribution

It clarifies that information preservation in black holes does not imply the conservation of baryon number or similar quantum numbers, highlighting a nuanced aspect of the information paradox.

Findings

Black holes can preserve quantum information without conserving baryon number.

Information-preserving black holes still violate certain global quantum numbers.

The paper clarifies misconceptions about the implications of black hole information preservation.

Abstract

It has been claimed recently that the black hole information-loss paradox has been resolved: the evolution of quantum states in the presence of a black hole is unitary and information preserving. We point out that, contrary to some claims in literature, information-preserving black holes still violate baryon number and any other quantum number which follows from an effective (and thus approximate) or anomalous symmetry.