Narrow Results

An entropy decrease phenomenon in the shock wave is studied. The statistical entropy of a unit mass system (UMS) is constructed based on statistical mechanics. Two terms in the microscopic statistical entropy are connected with the macroscopic entropy increment. In order to obtain the number density and velocity distribution function of argon gas, the direct simulation Monto Carlo method is adopted. The physical mechanism for entropy decrease phenomenon in the shock layer is revealed as compression work winning internal energy to produce the heat loss of a UMS.

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.