Quantum statistical entropy of Kerr-de Sitter black hole

By using the method of the membrane model, we derive the entropy of the black hole in non-thermal equilibrium states, and discuss the (n + 2)-dimensional de Sitter space-time. We show that the entropy of the black hole in the non-equilibrium state comprises two parts: one is the entropy corresponding to the black hole horizon; the other is the entropy corresponding to the cosmic horizon. Furthermore, we show that the entropy is the inherent property of the black hole and is irrelevant to the radiation field outside the horizon. This deepens our recognition of the relation between the entropy of the black hole and the area of the horizon. We provide a new way by which the bosonic and fermionic entropy of the black hole in higher dimensional non-equilibrium space-time is studied.