Isolated critical point from Lovelock gravity

TL;DR

This paper demonstrates the existence of a unique isolated critical point with non-standard critical exponents in Lovelock gravity, revealing complex phase transition behavior in hyperbolic vacuum black holes.

Contribution

It provides the first example of a critical point with non-standard critical exponents in a geometric gravity theory, specifically in Lovelock gravity with fine-tuned couplings.

Findings

Existence of an isolated critical point with non-standard exponents.

Two first-order phase transitions between small and large black holes.

Emergence of two swallowtails in the Gibbs free energy.

Abstract

For any K(=2k+1)th-order Lovelock gravity with fine-tuned Lovelock couplings, we demonstrate the existence of a special isolated critical point characterized by non-standard critical exponents in the phase diagram of hyperbolic vacuum black holes. In the Gibbs free energy this corresponds to a place wherefrom two swallowtails emerge, giving rise to two first-order phase transitions between small and large black holes. We believe that this is a first example of a critical point with non-standard critical exponents obtained in a geometric theory of gravity.