Notes on a quantum gravitational collaps

TL;DR

This paper discusses the conceptual and definitional challenges of quantum black holes, contrasting them with classical black holes, and explores the limitations of defining event horizons in quantum gravity.

Contribution

It highlights the difficulties in defining quantum black holes and the global nature of event horizons, emphasizing the differences from classical black hole models.

Findings

Classical event horizons are well-defined mathematically.

Quantum black holes lack a clear, universally accepted definition.

The global nature of event horizons complicates quantum descriptions.

Abstract

Everybody knows what the classical black holes are. In short, this is a spacetime region beyond the so-called event horizon. The notion of the event horizon is mathematically well defined. The situation with a definition of quantum black hole is not so clear. The problem is that the classical event horizon can be defined only globally, i.e. in order to be sure we have a black hole we would need an infinite time interval. But, in classical physics we have trajectories off all the particles and equations of motion for all the fields and can, in principle, construct some ideal models for the gravitational collapse and study the black hole formation under different conditions.