Holographic Ricci Dark Energy with Constant Bulk Viscosity in f(R,T) Gravity

Resumo

The holographic Ricci dark energy (HRDE) model is studied with bulk viscosity in modified f(R, T) gravity theory. We consider a universe filled with bulk viscous HRDE and pressureless dark matter. We obtain exact solutions and study the evolution of the scale factor and deceleration parameter and their transition from decelerated to accelerated expansion of the universe. The bulk viscosity coefficient is assumed to be constant. The behaviors concerning the cosmic expansion depend on the coupling parameter of f(R, T) and bulk viscous term. We apply two geometric diagnostics, the statefinder {r, s} and Om(z), to discriminate HRDE model from the ΛCDM model. We plot the evolution trajectories in the statefinder plane and Om(z) plane. We find that the viscous HRDE model behaves like quintessence at small values of the bulk-viscous term and like a Chaplygin gas at large values of the bulk-viscous term. However, the model approaches ΛCDM at late times of the evolution of the universe. We explore the obvious violation of energy-momentum conservation in f(R, T) gravity and provide a thermodynamic interpretation of extra terms generated by the nonminimal geometry-matter coupling describing particle production. We observe that the current acceleration of our universe is well explained with bulk viscosity.