Vacuum energy and the latent heat of AdS-Kerr black holes
  Phase transitions for rotating asymptotically anti-de Sitter black holes in four dimensions are described in the $P-T$ plane, in terms of the Hawking temperature and the pressure provided by the cosmological constant. The difference between constant angular momentum and constant angular velocity is highlighted, the former has a second order phase transition while the latter does not. If the angular momentum is fixed there a line of first order phase transitions terminating at a critical point with a second order phase transition and vanishing latent heat, while if the angular velocity is fixed there is a line of first order phase transitions terminating at a critical point with infinite latent heat. For constant angular velocity the analytic form of the phase boundary is determined, latent heats derived and the Clapeyron equation verified. 
Brian P. Dolan
gr-qc hep-th