The de Sitter/Anti- de Sitter Black Holes phase transition?

TL;DR

This paper explores phase transitions between different types of black holes in higher derivative gravity theories, focusing on thermodynamic stability and the implications of negative entropy states.

Contribution

It investigates the thermodynamics of Schwarzschild-Anti-de Sitter and Schwarzschild-de Sitter black holes in 5D higher derivative gravity, highlighting the emergence of negative entropy and potential phase transitions.

Findings

Negative entropy states can occur in higher derivative gravity black holes.

Phase transitions may involve transitions between negative and positive entropy black holes.

Negative entropy could signal new instabilities or require modified entropy definitions.

Abstract

We investigate the Schwarzschild-Anti-deSitter (SAdS) and SdS BH thermodynamics in 5d higher derivative gravity. The interesting feature of higher derivative gravity is the possibility for negative (or zero) SdS (or SAdS) BH entropy which depends on the parameters of higher derivative terms. The appearence of negative entropy may indicate a new type instability where a transition between SdS (SAdS) BH with negative entropy to SAdS (SdS) BH with positive entropy would occur or where definition of entropy should be modified.