Electron star birth: A continuous phase transition at nonzero density

TL;DR

This paper demonstrates that charged black holes in Anti-de Sitter space can undergo a third order phase transition at a critical temperature, involving a fermion fluid that carries charge and exhibits specific entropy scaling at low temperatures.

Contribution

It introduces a new phase transition mechanism involving fermion fluids in AdS black holes, extending the understanding of electron star solutions and their critical behavior.

Findings

Third order phase transition at critical temperature.

Fermion fluid carries charge in low temperature phase.

Entropy density scales as s~T^{2/z} at zero temperature.

Abstract

We show that charged black holes in Anti-de Sitter spacetime can undergo a third order phase transition at a critical temperature in the presence of charged fermions. In the low temperature phase, a fraction of the charge is carried by a fermion fluid located a finite distance from the black hole. In the zero temperature limit the black hole is no longer present and all charge is sourced by the fermions. The solutions exhibit the low temperature entropy density scaling s~T^{2/z} anticipated from the emergent IR criticality of recently discussed electron stars.