Singularity-free cosmic journey beyond the big bang: Insights from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si7.svg"> <mml:mrow> <mml:mi>f</mml:mi> <mml:mo>(</mml:mo> <mml:mi mathvariant="fraktur">R</mml:mi> <mml:mo>,</mml:mo> <mml:mi mathvariant="script">T</mml:mi> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> theory
Shamraiza Shabbir, M. Zeeshan Gul, M. Sharif, Nusrat Fatima
Abstract
This article examines the late time cosmic evolution in the presence of bulk viscous fluid defined by a specific viscosity coefficient ( ξ ) as ξ = ξ 0 ( t − τ 0 ) − 2 n H in the framework of f ( R , T ) gravity. In this context, R represents the Ricci scalar, T describes the trace of energy-momentum tensor, H is Hubble parameter, ξ 0 , τ 0 and n are positive constants. This study aims to explore the role of bulk viscosity in describing the dynamics of the early cosmos with a particular focus on the scenario of non-singular bounce. A particular form of the f ( R , T ) gravity model is chosen to assess how this modified gravity framework influences cosmic evolution. Moreover, we examine the conduct of various cosmological parameters to explore the presence of feasible cosmological bounce solutions. We also use linear perturbation to study the stability analysis. Our findings reveal the positive behavior of energy density, negative behavior of pressure as well as the violation of null energy condition and strong energy condition, which is required for the existence of viable bounce solutions. It is found that this gravitational theory effectively presents viable alternatives to the standard cosmological scenarios, hence providing valuable understanding of the gravitational force and the early universe.