De Sitter universe described by a binary mixture with a variable cosmological constant λ $\lambda $

Abstract

We have constructed a self-consistent system of Bianchi Type VI0 cosmology, and mingling of perfect fluid and dark energy in five dimensions. The usual equation of state \(p = \gamma \rho \) with \(\gamma \in [0, 1]\) is chosen by the perfect fluid. The dark energy assumed to be chosen is taken into consideration to be either the quintessence or Chaplygin gas. The same solutions pertaining to the corresponding the field equations of Einstein are obtained as a quadrature. State parameter’s equations for dark energy \(\omega \) is found to be consistent enough with the recent observations of SNe Ia data (SNe Ia data with CMBR anisotropy) and galaxy clustering statistics. Here our models predict that the rate of expansion of Universe would increase with passage of time. The cosmological constant \(\varLambda \) is traced as a declining function of time and it gets nearer to a small positive value later on which is supported by the results from the current supernovae Ia observations. Also a detail discussion is made on the physical and geometrical aspects of the models.