Black holes in Einsteinian cubic gravity

TL;DR

This paper constructs and analyzes black hole solutions in Einsteinian cubic gravity, revealing unique thermodynamic properties, phase transitions, and stability features across different dimensions.

Contribution

It provides the first explicit black hole solutions in Einsteinian cubic gravity and explores their thermodynamics, including novel equations of state and stability characteristics.

Findings

Black holes exhibit a quadratic pressure-temperature relation.

Presence of first order phase transitions with van der Waals behaviour.

Discovery of super-entropic black holes in higher dimensions.

Abstract

Using numerical and perturbative methods, we construct the first examples of black hole solutions in Einsteinian cubic gravity and study their thermodynamics. Focusing first on four dimensional solutions, we show that these black holes have a novel equation of state in which the pressure is a quadratic function of the temperature. Despite this, they undergo a first order phase transition with associated van der Waals behaviour. We then construct perturbative solutions for general $D \ge 5$ and study the properties of these solutions for $D=5$ and $D=6$ in particular. We note that for $D >4$ the solutions are described by two independent metric functions. We find novel examples of super-entropic behaviour over a large portion of the parameter space. We analyse the specific heat, determining that the black holes are thermodynamically stable over large regions of parameter space.