Massive Compact Objects in a Quantum Theory of Gravity

TL;DR

This paper argues that in a quantum gravity framework, massive compact objects like black holes lack singularities and horizons, evolving instead as standard quantum systems with many degrees of freedom, ensuring unitarity and predictability.

Contribution

It proposes that quantum gravity eliminates singularities and horizons in massive compact objects, leading to their evolution as quantum systems with many degrees of freedom.

Findings

Massive compact objects have no singularity.

Such objects also lack an event horizon.

They evolve as quantum systems with many degrees of freedom.

Abstract

A massive compact object is that which forms when a sufficiently massive star collapses. This is commonly taken to be a black hole with a singularity surrounded by a horizon and which evolves by emitting Hawking radiation. In a quantum theory of gravity, singularities are expected to be resolved and the evolutions are expected to be unitary. Assuming that such a theory with these properties exists, and with a few more physically motivated assumptions, we argue that a massive compact object has no singularity (by assumption) and must also have no horizon; otherwise, there may be a loss of predictability in the case of a black hole candidate observed today. With no singularity and also with no horizon, the massive compact object will then evolve as a standard quantum system with large number of interacting degrees of freedom.