Quantum black holes from null expansion operators

TL;DR

This paper introduces null expansion operators within a quantum gravity framework, enabling the classification of quantum black hole states and demonstrating horizon fluctuations, advancing understanding of black hole dynamics in quantum theory.

Contribution

It constructs null expansion operators in a quantum gravity setting, allowing for the definition and analysis of fully dynamical quantum black holes.

Findings

Quantum horizons fluctuate, confirming heuristic expectations.

Explicit quantum black hole states are constructed.

Framework for addressing black hole puzzles in quantum gravity.

Abstract

Using a recently developed quantization of spherically symmetric gravity coupled to a scalar field, we give a construction of null expansion operators that allow a definition of general, fully dynamical quantum black holes. These operators capture the intuitive idea that classical black holes are defined by the presence of trapped surfaces, that is surfaces from which light cannot escape outward. They thus provide a mechanism for classifying quantum states of the system into those that describe quantum black holes and those that do not. We find that quantum horizons fluctuate, confirming long-held heuristic expectations. We also give explicit examples of quantum black hole states. The work sets a framework for addressing the puzzles of black hole physics in a fully quantized dynamical setting.