Nonlinear viscous cosmological models in f(R,T)f(R,T) gravity
Abstract
This article presents nonlinear viscous cosmological model of the universe that arises in the modified gravity theory in which the Lagrangian of the gravitational action contains a general function f(R,T)f(R,T), where RR and TT denote the curvature scalar and the trace of the energy–momentum tensor, respectively, in the flat Friedmann-Robertson-Walker background metric with isotropic fluid. We obtain cosmological solutions in f(R,T)f(R,T) theory of gravity, specially for the choice f(R,T)=f(R)+f(T)f(R,T)=f(R)+f(T) with nonlinear viscosity described by nonlinear Israel Stewart theory. The physical and geometrical properties of the models in f(R,T)=α1R+α2Tf(R,T)=α1R+α2T gravity, where α1α1 and α2α2 are coupling parameters, with nonlinear Israel Stewart theory are studied in detail. The analysis of the variation of bulk viscous pressure, energy density, scale factor, Hubble parameter and deceleration parameter with cosmic evolution is done in the nonlinear Israel Stewart theory with f(R,T)f(R,T) gravity. The stability analysis of the equilibrium points of the dynamical system associated with the exponential evolution of the universe in f(R,T)f(R,T) gravity theory with nonlinear dissipative effects is also studied.
