Dark Energy with Generalized Equation of State in Bianchi Type-I Cosmological Model

Abstract

Dark energy with the usually used equation of state p=γρ, where γ=const < 0 is hydrodynamically unstable. To overcome this drawback we consider the cosmology of a perfect fluid with a linear equation of state of a more general form p=α(ρ-ρ0), where the constants α and ρ0 are free parameters. The anisotropic Bianchi type-I cosmological model filled with dark energy has been considered. A generalized equation of state for the dark energy component of the universe has been used. The exact solutions to the corresponding Einstein field equations and the statefinder diagnostic pair i. e. {r,s} parameters have been obtained in three interesting cases (i) when ρΛ > 0 and A > 0 (ii) when ρΛ > 0 and A > 0 and (iii) when ρΛ < 0 and A > 0 at the singularities i. e. t→0 and t→±∞. © 2011 Springer Science+Business Media, LLC.