Super-Entropic Black Holes

TL;DR

This paper introduces a new class of rotating AdS black holes with non-compact horizons, explores their thermodynamics, and challenges the Reverse Isoperimetric Inequality by showing their entropy exceeds the conjectured maximum.

Contribution

It constructs super-entropic black hole solutions in various dimensions and analyzes their thermodynamic properties, providing insights into the limits of the Reverse Isoperimetric Inequality.

Findings

Black holes with non-compact horizons have finite area and entropy.

These black holes violate the Reverse Isoperimetric Inequality.

The results suggest more restrictive conditions for the inequality to hold.

Abstract

We construct a new class of rotating AdS black hole solutions with non-compact event horizons of finite area in any dimension and study their thermodynamics. In four dimensions these black holes are solutions to gauged supergravity. We find that their entropy exceeds the maximum implied from the conjectured Reverse Isoperimetric Inequality, which states that for a given thermodynamic volume, the black hole entropy is maximized for Schwarzschild-AdS. We use this result to suggest more stringent conditions under which this conjecture may hold.