Restricted phase space thermodynamics of charged AdS black holes in conformal gravity

The thermodynamics of charged spherically symmetric AdS black holes in conformal gravity is revisited using the recently proposed restricted phase space(RPS) formalism.This formalism avoids all the bizarreness arising in the extended phase space formalism for this model.It is found that the charged AdS black holes in this model may belong to a new universality class that is different from all previously studied cases under the RPS formalism.Besides the distinguished isocharge T-S and isothermal Φ-Q_(e) behaviors,the absence of the Hawking-Page transition is another notable feature.However,in the high temperature limit,the thermodynamic behavior of the present model becomes exactly the same as that of the Einstein gravity and black hole scan models,which adds further evidence for the universality of the recently reported correspondence between high temperature AdS black holes and low temperature quantum phonon gases in nonmetallic crystals.