Entropy generation in 2+1-dimensional Gravity

TL;DR

This paper applies the tunneling approach to entropy generation in 3-D gravity, rederiving entropies of various horizons and analyzing differences from 4-D black holes, with implications for black hole evaporation.

Contribution

It demonstrates the validity of the tunneling method for entropy in 3-D gravity and explores unique features of 3-D black holes compared to 4-D cases.

Findings

Tunneling approach valid for 3-D gravity entropy calculations

Rederived entropies for de Sitter, Reissner-Nordström, and Bañados black holes

Identified differences in initial tunneling configurations for 3-D black holes

Abstract

The tunneling approach, for entropy generation in quantum gravity, is shown to be valid when applied to 3-D general relativity. The entropy of de Sitter and Reissner-Nordstr\"om external event horizons and of the 3-D black hole obtained by Ba\~nados et. al. is rederived from tunneling of the metric to these spacetimes. The analysis for spacetimes with an external horizon is carried out in a complete analogy with the 4-D case. However, we find significant differences for the black hole. In particular the initial configuration that tunnels to a 3-D black hole may not to yield an infinitely degenerate object, as in 4-D Schwarzschild black hole. We discuss the possible relation to the evaporation of the 3-D black hole.