A new class of Bianchi typeI cosmological models with viscosity and cosmological term

Abstract—Exact solutions of Einstein’s field equations for a Bianchi type-I space-time filled with a dissipative fluid and cosmological term Λ are investigated. To get deterministic solution we choose the scale factor a(t) = tnet, where n is a positive constant. This choice of the scale factor yields a time dependent deceleration parameter (DP), representing a model which generates a transition of the universe from the early decelerating phase to the recent accelerating phase. In this paper we generalize the recent results of Yadav et al. [27]. We find a variety of solutions in Bianchi type-I space-time for different values of n with variable and constant viscosity and cosmological constant. The cosmological constant Λ(t) is found to be in good agreement with recent supernovae Ia observations. The cosmic jerk parameter is also found to be in good concordance with the recent data of astrophysical observations under appropriate condition. The physical and geometric properties of the derived models are discussed in the light of thermodynamic. Index Terms—Bianchi type-I models; Entropy; Variable deceleration parameter; Cosmological constant PACS number: 98.80.Es, 98.80.C