Realistic clocks, universal decoherence and the black hole information paradox

TL;DR

This paper explores how realistic clocks introduce fundamental decoherence in quantum mechanics, which can resolve the black hole information paradox by causing information loss before black hole evaporation.

Contribution

It demonstrates that incorporating realistic clocks leads to universal decoherence, providing a mechanism to resolve the black hole information paradox.

Findings

Universal decoherence rate is sufficient to erase information before black hole evaporation.

Realistic clocks cause non-unitary evolution in quantum mechanics.

Previous models underestimated the rate of information loss.

Abstract

Ordinary quantum mechanics is formulated on the basis of the existence of an ideal classical clock external to the system under study. This is clearly an idealization. As emphasized originally by Salecker and Wigner and more recently by other authors, there exist limits in nature to how ``classical'' even the best possible clock can be. When one introduces realistic clocks, quantum mechanics ceases to be unitary and a fundamental mechanism of decoherence of quantum states arises. We estimate the rate of universal loss of unitarity using optimal realistic clocks. In particular we observe that the rate is rapid enough to eliminate the black hole information puzzle: all information is lost through the fundamental decoherence before the black hole can evaporate. This improves on a previous calculation we presented with a sub-optimal clock in which only part of the information was lost by the time of evaporation.