Abstract
The objective of this paper is to investigate the thermodynamic properties of McVittie universe. It turns out that the Einstein field equations are obtained by using Clausius equation near apparent horizon of McVittie universe. For the existence of horizons, different conditions in terms of McVittie parameters are discussed. Diverse cases of surface gravity are studied and conditions in terms of parameters for which surface gravity is positive, zero and negative are obtained and analyzed. It is shown that the generalized second law (GSL) holds near the apparent horizon if R ˙ A > 0 . Our results show that the heat capacity, C P , of the universe is always negative for matter dominated phase having P = 0. On the other hand, when P > 0 , the heat capacity C P > 0 provided R A > 2 / 8 π P − 3 H 2 and negative otherwise. Furthermore, when P > 0 , the temperature of the universe is minimum at R min = 2 / 8 π P − 3 H 2 while its heat capacity diverges.