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

摘要

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 the baryon number and any other quantum number which follows from an effective (and thus approximate) or anomalous symmetry.