Quintessence Behavior of an Anisotropic Bulk Viscous Cosmological Model in Modified <i>f</i>(<i>Q</i>)-Gravity

Abstract

In this article, we consider an anisotropic viscous cosmological model having LRS Bianchi type I spacetime with f(Q) gravity. We investigate the modified f(Q) gravity with form f(Q)=αQ2+β, where Q is the non-metricity scalar and α, β are the positive constants. From the modified Einstein’s field equation having the viscosity coefficient ξ(t)=ξ0H, the scale factor is derived as a(t)=2sinhm+26ξ0α(2m+1)t. We apply the observational constraints on the apparent magnitude m(z) using the χ2 test formula with the observational data set such as JLA, Union 2.1 compilation and obtained the best approximate values of the model parameters m,α,H0,ξ0. We find a transit universe which is accelerating at late times. We also examined the bulk viscosity equation of state (EoS) parameter ωv and derived its current value satisfying ωv−1/3, which shows the dark energy dominating universe evolution having a cosmological constant, phantom, and super-phantom evolution stages. It tends to the Λ cold dark matter (ΛCDM) value (ωv=−1) at late times. We also estimate the current age of the universe as t0≈13.6 Gyrs and analyze the statefinder parameters with (s,r)→(0,1) as t→∞.

Keywords

• bulk viscosity
• <i>f</i>(<i>Q</i>) gravity
• accelerating universe
• LRS Bianchi type-I universe
• observational constraints