Critical black holes in a large charge limit

Abstract

The extended thermodynamics of Reissner–Nordström charged black holes in D-dimensional anti-de Sitter spacetime has a phase structure in the (T, p) plane that includes a line of first-order phase transitions ending in a second-order transition point. For each D[Formula: see text][Formula: see text]4, properties of the critical black hole at that point are explored, motivated by the observation that in D[Formula: see text][Formula: see text]4 its neighborhood plays a core role in defining a very special class of heat engines that asymptote to Carnot efficiency in the large charge limit. This new limit provides a model of a novel low-temperature thermodynamic system. The double limit of approaching the horizon while sending the charge large at an appropriate rate yields a fully decoupled D-dimensional Rindler spacetime with zero cosmological constant.