Reexploration of interacting holographic dark energy model: Cases of interaction term excluding the Hubble parameter

TL;DR

This paper analyzes five variants of interacting holographic dark energy models with different interaction terms, constraining them using multiple cosmological data sets, and finds that current observations do not favor one model over the others.

Contribution

It provides a comprehensive observational comparison of five new interaction terms in holographic dark energy models excluding the Hubble parameter.

Findings

All models fit the data equally well with similar chi-squared values.

Current data do not prefer any specific interaction term among the models.

Comparison with models involving Hubble parameter interaction is also discussed.

Abstract

In this paper, we make a deep analysis for the five typical interacting holographic dark energy models with the interaction terms $Q=3\beta H_{0}\rho_{\rm{de}}$, $Q=3\beta H_{0}\rho_{\rm{c}}$, $Q=3\beta H_{0}(\rho_{\rm{de}}+\rho_{\rm c})$, $Q=3\beta H_{0}\sqrt{\rho_{\rm{de}}\rho_{\rm c}}$, and $Q=3\beta H_{0}\frac{\rho_{\rm{de}}\rho_{c}}{\rho_{\rm{de}}+\rho_{\rm c}}$, respectively. We obtain observational constraints on these models by using the type Ia supernova data (the Joint Light-curve Analysis sample), the cosmic microwave background data (Planck 2015 distance priors), the baryon acoustic oscillations data, and the direct measurement of the Hubble constant. We find that the values of $\chi_{\rm min}^2$ for all the five models are almost equal (around~699), indicating that the current observational data equally favor these IHDE models. In addition, a comparison with the cases of interaction term involving the Hubble parameter $H$ is also made.