A Universal Lower Bound on the Specific Temperatures of AdS-Reissner-Nordstrom Black Holes with Flat Event Horizons

TL;DR

This paper establishes a universal lower bound on the specific temperature of AdS-Reissner-Nordstrom black holes with flat horizons in higher-dimensional gravitational theories, supporting the idea that such black holes cannot be arbitrarily cold.

Contribution

It proves a universal lower bound on the temperature of these black holes, extending previous conjectures and providing insights into their thermodynamic limits in the context of AdS/CFT correspondence.

Findings

The specific temperature is bounded below by approximately 0.156875.

No such black hole can be arbitrarily cold in the considered theories.

Supports the idea that low-temperature degrees of freedom are not hidden behind horizons.

Abstract

We show that, in a gravitational theory [in any number of dimensions greater than 3] which admits BPS branes and AdS-Reissner-Nordstrom black holes with flat event horizons, the specific [dimensionless] temperature of such a black hole is bounded below by approximately 0.156875. This confirms the recent suggestion by Hartnoll and Tavanfar, to the effect that no such black hole can be arbitrarily cold, since from the AdS/CFT dual point of view the low-temperature degrees of freedom should not be concealed by the equivalent of an event horizon.