Holographic dark energy with time varying $c^2$ parameter

TL;DR

This paper explores a generalized holographic dark energy model with a slowly varying parameter c^2, analyzing its effects on cosmic acceleration, equation of state, and diagnostic trajectories.

Contribution

It introduces a time-dependent c^2 parameter in holographic dark energy, examining its impact on cosmic evolution and statefinder diagnostics.

Findings

The model's equation of state can enter the phantom regime earlier or later.

The transition from deceleration to acceleration is affected by c^2.

Statefinder trajectories depend strongly on the time-varying c^2 parameter.

Abstract

We consider the holographic dark energy model in which the model parameter $c^2$ evolves slowly with time. First we calculate the evolution of EoS parameter as well as the deceleration parameter in this generalized version of holographic dark energy (GHDE). Depending on the parameter $c^2$, the phantom regime can be achieved earlier or later compare with original version of holographic dark energy. The evolution of energy density of GHDE model is investigated in terms of parameter $c^2$. We also show that the time-dependency of $c^2$ can effect on the transition epoch from decelerated phase to accelerated expansion. Finally, we perform the statefinder diagnostic for GHDE model and show that the evolutionary trajectories of the model in $s-r$ plane are strongly depend on the parameter $c^2$.