Study of QCD generalized ghost dark energy in FRW universe

TL;DR

This paper investigates a generalized ghost dark energy model within the FRW universe, incorporating a term dependent on Hubble parameter and its square, and demonstrates its stability and consistency with observational data indicating late-time cosmic acceleration.

Contribution

It introduces a novel dark energy model with a linear and quadratic dependence on Hubble parameter, analyzing its stability and observational viability.

Findings

The universe remains stable under this model.

The model predicts a transition to accelerated expansion at redshift ~0.617.

It aligns well with current observational data.

Abstract

A phenomenological generalized ghost dark energy model has been studied under the framework of FRW universe. In ghost dark energy model the energy density depends linearly on Hubble parameter (H) but in this dark energy model, the energy density contains a the sub-leading term which is depends on $\mathcal{O} (H^2)$, so the energy density takes the form $\rho_D=\alpha H+ \beta H^2$, where $\alpha$ and $\beta$ are the constants. The solutions of the Friedman equation of our model leads to a stable universe. We have fitted our model with the present observational data including Stern data set. With the help of best fit results we find the adiabatic sound speed remains positive throughout the cosmic evolution, that claims the stability of the model. The flipping of the signature of deceleration parameter at the value of scale factor $a=0.5$ indicates that the universe is at the stage of acceleration i.e. de Sitter phase of the universe at late time. Our model shows that the acceleration of the universe begin at redshift $z_{ace}\approx 0.617$ and the model is also consistent with the current observational data.