Black holes without boundaries

TL;DR

This paper explores alternative definitions of black hole boundaries using trapping horizons instead of event horizons, discussing their thermodynamic properties and implications for quantum gravity and information loss.

Contribution

It introduces trapping horizons as a boundary concept for black holes, offering a potentially more physically meaningful framework than event horizons.

Findings

Trapping horizons exhibit thermodynamic behavior.

They may produce Hawking radiation.

Implications for resolving black hole information paradox.

Abstract

We discuss some of the drawbacks of using event horizons to define black holes and suggest ways in which black holes can be described without event horizons, using trapping horizons. We show that these trapping horizons give rise to thermodynamic behavior and possibly Hawking radiation too. This raises the issue of whether the event horizon or the trapping horizon should be seen as the true boundary of a black hole. This difference is important if we believe that quantum gravity will resolve the central singularity of the black hole and clarifies several of the issues associated with black hole thermodynamics and information loss.