Anisotropic cosmological models with a perfect fluid and a $\Lambda$ term

TL;DR

This paper investigates the evolution of Bianchi type-I cosmological models incorporating a perfect fluid, dark energy via a cosmological constant, and explores how the $b3$ term influences the universe's dynamics.

Contribution

It introduces a self-consistent model combining perfect fluid and dark energy with a $b3$ term, analyzing their combined effects on anisotropic universe evolution.

Findings

The $b3$ term significantly affects the universe's anisotropic evolution.

Dark energy with a cosmological constant influences the isotropization process.

Different equations of state alter the universe's expansion dynamics.

Abstract

We consider a self-consistent system of Bianchi type-I (BI) gravitational field and a binary mixture of perfect fluid and dark energy given by a cosmological constant. The perfect fluid is chosen to be the one obeying either the usual equation of state, i.e., $p = \zeta \ve$, with $\zeta \in [0, 1]$ or a van der Waals equation of state. Role of the $\Lambda$ term in the evolution of the BI Universe has been studied.