Simple Bianchi cosmologies with anisotropic Segre [1(11,1)] dark energy

TL;DR

This paper investigates anisotropic Bianchi cosmological models with Segre type [1(11,1)] dark energy, deriving new parameterizations and exploring their behaviors through analytical and numerical methods.

Contribution

It introduces new closed-form parameterizations for specific stress conditions in anisotropic Bianchi universes with Segre type [1(11,1)] dark energy.

Findings

Derived closed-form solutions for zero and equal stresses cases.

Identified conditions for all stresses being equal with explicit parameterizations.

Numerically illustrated behaviors when the distinct stress is negative of degenerate stresses.

Abstract

In this paper, we use a sample anisotropic but spatially homogeneous metric to look at the properties of Segre type [1(11,1)] universes, that behave like vacuum energy along a spatial plane (two stresses equal to the negative density) but have distinct stress along the third spatial axis. We examine situations with simple relationships between the distinct and degenerate stresses, finding a closed form parameterizations for the case where the distinct stress is equal to zero and finding new conditions in which the case with all stresses equal has a closed form parameterization. We also use numerical methods to illustrate possible behaviors for the case where the distinct stress is the negative of the degenerate stresses.