Quintessence Behaviour of an Anisotropic Bulk Viscous Cosmological Model in Modified $f(Q)$-Gravity

Abstract

In this article, we have discussed the results of our investigation. We consider an anisotropic viscous cosmological model of (LRS) Bianchi type I spacetime universe filled with a viscous fluid under $f(Q)$ gravity. We have studied the modified $f(Q)$ gravity with quadratic form $f(Q)=\alpha Q^{2}+\beta$, where $Q$ is called as a non-metricity scalar and $\alpha $, $\beta$ are positive constants. We obtain the modified Einstein field equation by considering the viscosity coefficient $\xi(t)=\xi_{0}H$ and obtained the scale factor $a(t)=2~sinh\left (\frac{m+ 2} {6}\sqrt{\frac{\xi_{0}}{\alpha(2m+1)}}t\right)$.We applied the observational constraint on the apparent magnitude $m(z)$ using the $\chi^{2}$ test formula with observational data set like JLA or Union 2.1 compilation and obtained the best approximate values of the model parameters ${ m,\alpha, H_{0} \xi_{0}}$. We have analyzed our model and found a transit phase quintessence anisotropic accelerating universe. We also examined the bulk viscosity equation of state (EoS) parameter $\omega_{v}$ and obtained its current value as $\omega_{v}<-1/3$, which shows the dark energy dominant model, cosmological constant, phantom, and super-phantom dark energy models, and tends to the $\Lambda$CDM value ($\omega_{v}=-1$) in the late time. We also estimate the current age of the universe as $t_{0}\approx13.6$ Grys and analyze the Statefinder parameters with $(s,r)\to(0,1)$ as $t \to \infty$.