BTZ Black Holes and Flat Space Cosmologies in Higher Derivative Theories

TL;DR

This paper investigates BTZ black holes and flat space cosmologies within higher derivative gravity theories in 2+1 dimensions, demonstrating entropy matches across bulk and field theory and analyzing phase transition behaviors.

Contribution

It proves the entropy correspondence between bulk Iyer-Wald entropy and field theory entropy for various symmetry algebras in higher derivative theories.

Findings

Entropy matches between bulk and field theory for multiple symmetry algebras.

No phase transition occurs in the flat case within the grand canonical ensemble.

Analysis of phase transitions in higher curvature gravity theories.

Abstract

We consider BTZ black holes and flat space cosmologies in generic higher derivative gravity theories in 2+1 dimensions. Our goal is to prove the match between the bulk Iyer-Wald entropy and the field theory entropy for various symmetry algebras (CFT$_2$, Warped CFT$_2$, BMS$_3$). We also discuss phase transitions in higher curvature theories, and argue that, in the flat case, there is strictly speaking no phase transition in the grand canonical ensemble.