Statefinder hierarchy model for the Barrow holographic dark energy

TL;DR

This paper applies the state finder hierarchy and composite null diagnostic tools to the Barrow holographic dark energy model within the FLRW universe, providing new methods to differentiate dark energy models and break parameter degeneracies.

Contribution

It introduces the use of state finder hierarchy and composite null diagnostic tools specifically for the BHDE model, enhancing model differentiation capabilities.

Findings

State finder hierarchy effectively distinguishes BHDE from ΛCDM.

Composite null diagnostic trajectories reveal differences in dark energy models.

Combination with growth rate helps break parameter degeneracies.

Abstract

In this paper, we have used the state finder hierarchy for Barrow holographic dark energy (BHDE) model in the system of the FLRW Universe. We apply two DE diagnostic tools to determine $\Lambda BHDE$ model to have various estimations of $\triangle$. The first diagnostic tool is the state finder hierarchy in which we have studied $S^{(1)}_{3}$ $S^{(1)}_{4}$, $S^{(2)}_{3}$ $S^{(2)}_{4}$ and second is the composite null diagnostic (CND) in which the trajectories ( $S^{(1)}_{3} - \epsilon$), ($S^{(1)}_{4}-\epsilon$), ($S^{(2)}_{3}-\epsilon$)($S^{(2)}_{4}-\epsilon$) are discussed, where $\epsilon$ is fractional growth parameter. The infrared cut-off here is taken from the Hubble horizon. Finally, together with the growth rate of matter perturbation, we plot the state finder hierarchy that determines a composite null diagnosis that can differentiate emerging dark energy from $\Lambda CDM$. In addition, the combination of the hierarchy of the state finder and the fractional growth parameter has been shown to be a useful tool for diagnosing BHDE, particularly for breaking the degeneracy with different parameter values of the model.