Imperfect fluid cosmological model in modified gravity

Abstract

In this article, we considered the bulk viscous fluid in the formalism of modified gravity in which the general form of a gravitational action is $f(R,T)$ function, where $R$ is the curvature scalar and $T$ is the trace of the energy momentum tensor within the frame of flat FRW space time. The cosmological model dominated by bulk viscous matter with total bulk viscous coefficient expressed as a linear combination of the velocity and acceleration of the expansion of the universe in such a way that $\xi ={\xi }_0+{\xi }_1\frac{\dot{a}}{a}+{\xi }_2\frac{\ddot{a}}{\dot{a}}$, where ${\xi }_0$, ${\xi }_1$ and ${\xi }_2$ are constants. We take $p=(\gamma -1)\rho$, where $0\le \gamma \le 2$ as an equation of state for perfect fluid. The exact solutions to the corresponding field equations are obtained by assuming a particular model of the form of $f(R,T)=R+2f(T)$, where $f(T)=\lambda T$, $\lambda$ is constant. We studied the four possible scenarios for different values of $\gamma$, such as $\gamma =0$, $\gamma =\frac{2}{3}$, $\gamma =1$ and $\gamma =\frac{4}{3}$ with the possible positive and negative ranges of $\lambda$ to observe the accelerated expansion history of the universe. Finally, a big-rip singularity is observed.

19 pages, references added, conclusion section is rewritten and possible future work is given

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Cited by in corpus (6)

• Cosmic acceleration with bulk viscosity in modified $f(Q)$ gravity
• Wormhole Modeling Supported by Non-Exotic Matter
• Physical Parameters for Stable $f(R)$ Models
• The trace of the trace of the energy-momentum tensor-dependent Einstein's field equations
• Effective equation of state in modified gravity and observational constraints
• Cosmic Evolution of the Kantowski-Sachs Universe in the Context of a Bulk Viscous String in Teleparallel Gravity