White Holes as Remnants: A Surprising Scenario for the End of a Black Hole

TL;DR

This paper proposes that black holes can quantum tunnel into white holes, which act as long-lived remnants, providing a consistent, unitary resolution to the black hole information paradox within established physics.

Contribution

It demonstrates that white-hole remnants are physically plausible and can resolve the information paradox without violating known physics.

Findings

White holes with small masses and large interiors are consistent with established physics.

Black holes can tunnel into white holes at the end of evaporation.

White-hole remnants can evade no-go arguments and are stable.

Abstract

Quantum tunneling of a black hole into a white hole provides a model for the full life cycle of a black hole. The white hole acts as a long-lived remnant, solving the black-hole information paradox. The remnant solution of the paradox has long been viewed with suspicion, mostly because remnants seemed to be such exotic objects. We point out that (i) established physics includes objects with precisely the required properties for remnants: white holes with small masses but large finite interiors; (ii) non-perturbative quantum-gravity indicates that a black hole tunnels precisely into such a white hole, at the end of its evaporation. We address the objections to the existence of white-hole remnants, discuss their stability, and show how the notions of entropy relevant in this context allow them to evade several no-go arguments. A black hole's formation, evaporation, tunneling to a white hole, and final slow decay, form a unitary process that does not violate any known physics.