Bianchi Type-I Anisotropic Dark Energy Models with Constant Deceleration Parameter

TL;DR

This paper develops new anisotropic dark energy models in Bianchi type-I space-time with constant deceleration, solving Einstein's equations for power-law and exponential scale factors, and finds results consistent with recent cosmological observations.

Contribution

It introduces novel anisotropic dark energy models with variable EoS and constant deceleration, solving Einstein's equations for different expansion laws.

Findings

EoS parameter $$ varies with time and aligns with observational data.

Cosmological constant $$ decreases over time, approaching a small positive value.

Models are consistent with supernovae Ia, CMBR anisotropy, and galaxy clustering observations.

Abstract

New dark energy models in anisotropic Bianchi type-I (B-I) space-time with variable EoS parameter and constant deceleration parameter have been investigated in the present paper. The Einstein's field equations have been solved by applying a variation law for generalized Hubble's parameter in B-I space-time. The variation law for Hubble's parameter generates two types of solutions for the average scale factor, one is of power-law type and other is of the exponential form. Using these two forms, Einstein's field equations are solved separately that correspond to expanding singular and non-singular models of the universe respectively. The equation of state (EoS) parameter $\omega$ is found to be time dependent and its existing range for this model is in good agreement with the recent observations of SNe Ia data, SNe Ia data (with CMBR anisotropy) and galaxy clustering statistics. The cosmological constant $\Lambda$ is found to be a decreasing function of time and it approaches a small positive value at late time (i.e. the present epoch) which is corroborated by results from recent supernovae Ia observations.