# Phase Space Analysis for Anisotropic Universe with Nonlinear Bulk Viscosity

## TL;DR

This paper analyzes the stability and phase space behavior of an anisotropic universe model with nonlinear bulk viscosity, revealing conditions for stable solutions and different cosmic phases.

## Contribution

It introduces a phase space analysis of an anisotropic universe with nonlinear bulk viscosity, highlighting stability conditions and the impact of viscosity parameters.

## Key findings

- Stable solutions exist with nonlinear bulk viscosity.
- Exponential expansion occurs only within specific parameter ranges.
- Different universe phases are characterized by power-law scale factors.

## Abstract

In this paper, we discuss the phase space analysis of locally rotationally symmetric Bianchi type I universe model by taking a noninteracting mixture of dust like and viscous radiation like fluid whose viscous pressure satisfies a nonlinear version of the Israel-Stewart transport equation. An autonomous system of equations is established by defining normalized dimensionless variables. In order to investigate the stability of the system, we evaluate corresponding critical points for different values of the parameters. We also compute the power-law scale factor whose behavior indicates different phases of the universe model. It is found that our analysis does not provide a complete immune from fine-tuning because the exponentially expanding solution occurs only for a a particular range of parameters. We conclude that stable solutions exist in the presence of nonlinear model for bulk viscosity with different choices of the constant parameter $m$ for anisotropic universe.