Reverse Hawking-Page phase transition in de Sitter black holes

Abstract

In the context of black hole chemistry, we study the thermodynamics of asymptotically de Sitter black holes with conformal scalar hair in Einstein gravity. The hair parameter allows us to attain thermodynamic equilibrium between the event horizon and the cosmological horizon. We find that the system of the black hole and the de Sitter space surrounding it undergo a “Reverse” Hawking-Page phase transition provided we consider the grand-canonical ensemble.