A "black hole theorem," and its implications

TL;DR

This paper formulates a 'black hole theorem' that explores the fundamental conflict in the black hole information problem, emphasizing the quantum subsystem nature of black holes and implications for quantum gravity and observational signatures.

Contribution

It introduces a general 'black hole theorem' framing black holes as quantum subsystems, sharpening the understanding of their interactions and implications for quantum gravity.

Findings

Black holes can be modeled as quantum subsystems within a larger system.

Interactions between black holes and their environment may extend beyond local quantum field descriptions.

Implications for observational signatures in electromagnetic and gravitational wave data.

Abstract

A general formulation of the basic conflict of the information problem is given, encapsulated in a "black hole theorem." This is framed in a more general context than the usual one of quantum field theory on a background, and is based on describing a black hole as a quantum subsystem of a larger system, including its environment. This sharpens the limited set of possible consistent options; as with the Coleman-Mandula theorem, the most important point is probably the loophole in the "theorem," and what this tells us about the fundamental structure of quantum gravity. This "theorem" in particular involves the general question of how to define quantum subsystems in quantum gravity. If black holes do behave as quantum subsystems, at least to a good approximation, evolve unitarily, and do not leave remnants, the "theorem" implies the presence of interactions between a black hole and its environment that go beyond a description based on local quantum fields. This provides further motivation for and connects to previous work giving a principled parameterization of these interactions, and investigating their possible observational signatures via electromagnetic or gravitational wave observations of black holes.