On Phase Transition Behaviors of Kerr-Sen Black Hole

TL;DR

This paper studies the phase transition behaviors of Kerr-Sen black holes, revealing second-order phase transitions and critical phenomena consistent with mean field theory through thermodynamical analysis and geothermodynamics.

Contribution

It introduces a new metric form based on the Gibbs free energy to analyze phase transitions and calculates critical exponents matching mean field theory.

Findings

Kerr-Sen black holes undergo second-order phase transitions.

The geothermodynamical scalar curvature indicates similar phase transitions.

Critical exponents align with mean field theory predictions.

Abstract

We investigate phase transitions and critical behaviors of the Kerr-Sen black hole in four dimensions. Computing the involved thermodynamical quantities including the specific heat and using the Ehrenfest scheme, we show that such a black hole undergoes a second-order phase transition. Adopting a new metric form derived from the Gibss free energy scaled by a conformal factor associated with extremal solutions, we calculate the geothermodynamical scalar curvature recovering similar phase transitions. Then, we obtain the scaling laws and the critical exponents, matching perfectly with mean field theory.