Anisotropic Bianchi Type-I Model with a Varying Λ Term

Einstein field equations with variable gravitational and cosmological constants are considered in the presence of a perfect fluid for a Bianchi type-I universe by assuming that the cosmological term is proportional to the Hubble parameter. The variation law for vacuum density was recently proposed by Schützhold on the basis of quantum field estimation in a curved expanding background. The cosmological term tends asymptotically to a genuine cosmological constant and the model tends to a de Sitter universe. We obtain that the present universe is accelerating with a large fraction of cosmological density in the form of a cosmological term.