Classical and Quantum Equations of Motion of an n-dimesional BTZ Black Hole

TL;DR

This paper studies the classical and quantum dynamics of an n-dimensional BTZ black hole's gravitational collapse, revealing quantum effects that can remove the classical singularity and exhibit non-local behavior.

Contribution

It derives a generic method for calculating the conserved mass of a spherically symmetric shell and analyzes quantum effects near the singularity and horizon.

Findings

Quantum effects remove the classical singularity at the origin.

Classical collapse time is infinite for an asymptotic observer.

Quantum effects near the horizon do not alter classical conclusions.

Abstract

We investigate the gravitational collapse of a non-rotating $n$-dimensional BTZ black hole in AdS space in the context of both classical and quantum mechanics. This is done by first deriving the conserved mass of a "spherically" symmetric domain wall, which is taken as the classical Hamiltonian of the black hole. Upon deriving the conserved mass, we also point out that, for a "spherically" symmetric shell, there is an easy and straight-forward way of determining the conserved mass, which is related to the proper time derivative of the interior and exterior times. This method for determining the conserved mass is generic to any situation (i.e. any equation of state), since it only depends on the energy per unit area, $\sigma$, of the shell. Classically, we show that the time taken for gravitational collapse follows that of the typical formation of a black hole via gravitational collapse, that is, an asymptotic observer will see that the collapse takes an infinite amount of time to occur, while an infalling observer will see the collapse to both the horizon and the classical singularity occur in a finite amount of time. Quantum mechanically, we take primary interest in the behavior of the collapse near the horizon and near the classical singularity from the point of view of both asymptotic and infalling observers. In the absence of radiation and fluctuations of the metric, quantum effects near the horizon do not change the classical conclusions for an asymptotic observer. The most interesting quantum mechanical effect comes in when investigating near the classical singularity. Here, we find, that the quantum effects in this region are able to remove the classical singularity at the origin, since the wave function is non-singular, and is also displays non-local effects, which depend on the energy density of the domain wall.