Anisotropic dark energy model with a hybrid scale factor

TL;DR

This paper develops an anisotropic dark energy model with a hybrid scale factor in Bianchi type V space-time, showing dynamic pressure anisotropies that persist over cosmic time and lead to late-time acceleration similar to the Lambda-CDM model.

Contribution

It introduces a novel anisotropic dark energy model with a hybrid scale factor that captures the transition from deceleration to acceleration in an anisotropic universe.

Findings

Pressure anisotropies evolve dynamically and persist at late times.

The model enters a phantom region at late cosmic phases.

It overlaps with Lambda-CDM at late times.

Abstract

Anisotropic dark energy model with dynamic pressure anisotropies along different spatial directions is constructed at the backdrop of a spatially homogeneous diagonal Bianchi type $V$ $(BV)$ space-time in the framework of General Relativity. A time varying deceleration parameter generating a hybrid scale factor is considered to simulate a cosmic transition from early deceleration to late time acceleration. We found that the pressure anisotropies along the $y-$ and $z-$ axes evolve dynamically and continue along with the cosmic expansion without being subsided even at late times. The anisotropic pressure along the $x-$axis becomes equal to the mean fluid pressure. At a late phase of cosmic evolution, the model enters into a phantom region. From a state finder diagnosis, it is found that the model overlaps with $\Lambda$CDM at late phase of cosmic time.