Black Hole Cannibalism

TL;DR

This paper explores a thought experiment where a black hole consumes another black hole, examining the implications for information recovery and proposing decoherence as a resolution to the paradox.

Contribution

It introduces a novel variant of the Hayden-Preskill experiment involving black hole-to-black hole messages and discusses potential resolutions to the resulting paradox.

Findings

Existence of a recovery channel implies information can be retrieved without horizon proximity

Sharpened black hole information paradox for distant observers

Decoherence mechanisms may resolve the paradox

Abstract

We consider a version of the Hayden-Preskill thought experiment in which the message thrown into the black hole is itself a smaller black hole. We then discuss the implications of the existence of a recovery channel for this black hole message at asymptotic infinity, resulting in a sharpening of the black hole information paradox for observers who never need to approach a horizon. We suggest decoherence mechanisms as a way of resolving this sharpened paradox.