The fate of black branes in Einstein-Gauss-Bonnet gravity

TL;DR

This paper investigates the stability and phase transitions of black branes in Einstein-Gauss-Bonnet gravity, revealing how the Gauss-Bonnet coupling sign influences their evolution, stability, and critical behavior.

Contribution

It provides a detailed analysis of black brane stability in EGB gravity, identifying conditions for avoiding instabilities and characterizing phase transition points.

Findings

Positive ppa allows stable black branes for large ratios.

Negative ppa leads to inevitable Gregory-Laflamme instability.

Phase transition line ends at a second order transition point.

Abstract

Black branes are studied in Einstein-Gauss-Bonnet (EGB) gravity. Evaporation drives black branes towards one of two singularities depending on the sign of $\alpha$, the Gauss-Bonnet coupling. For positive $\alpha$ and sufficiently large ratio $\sqrt{\alpha}/L$, where $L/2\pi$ is the radius of compactification, black branes avoid the Gregory-Laflamme (GL) instability before reaching a critical state. No black branes with the radius of horizon smaller than the critical value can exist. Approaching the critical state branes have a nonzero Hawking temperature. For negative $\alpha$ all black branes encounter the GL instability. No black branes may exist outside of the interval of the critical values, $0\leq\beta<3$, where $\beta=1- 8\alpha/r_h^2$ and $r_h$ is the radius of horizon of the black brane. The first order phase transition line of GL transitions ends in a second order phase transition point at $\beta=0$.