Viscous extended holographic Ricci dark energy in the framework of standard Eckart theory

TL;DR

This paper investigates a viscous extended holographic Ricci dark energy model using Eckart theory, showing it can mimic the cosmological constant at late times and satisfy thermodynamic laws.

Contribution

It introduces a viscous EHRDE model within Eckart theory and analyzes its cosmological behavior, stability, and thermodynamic consistency, which is a novel approach.

Findings

EoS behaves like 'quintom' and aligns with observational constraints.

Model can approach ΛCDM phase in the late universe.

The generalized second law of thermodynamics holds in the model.

Abstract

In the present work we report a study on the viscous extended holographic Ricci dark energy (EHRDE) model under the assumption of existence of bulk viscosity in the linear barotropic fluid and the EHRDE in the framework of standard Eckart theory of relativistic irreversible thermodynamics and it has been observed that the non-equilibrium bulk viscous pressure is significantly smaller than the local equilibrium pressure. We have studied the equation of state (EoS) parameter and observed that the EoS behaves like "quintom" and is consistent with the constraints set by observational data sets from SNLS3, BAO and Planck + WMAP9 + WiggleZ measurements in the reference S. Kumar and L. Xu, \emph{Phys. Lett. B},\textbf{737}, 244 (2014). Analysis of statefinder parameters has shown the possibility of attainment of $\Lambda$CDM phase under current model and at the same time it has been pointed out that the for $z=0$ i.e. current universe, the statefinder pair is different from that of $\Lambda$CDM and the $\Lambda$CDM can be attained in a later stage of the universe. An analysis of stability has shown that although the viscous EHRDE along with viscous barotropic is classically unstable in the present epoch, it can lead to a stable universe in very late stage. Considering an universe enveloped by event horizon we have observed validity of generalized second law of thermodynamics.