Cosmic Constraints on Holographic Dark Energy in Brans-Dicke Theory

TL;DR

This study tests holographic dark energy within Brans-Dicke theory against cosmic data, finds best-fit parameters indicating an accelerating universe with phantom-like dark energy, and explores the evolution of Newton's constant.

Contribution

It provides observational constraints on holographic dark energy in Brans-Dicke theory, including parameter estimation and implications for cosmic acceleration.

Findings

Universe is accelerating with phantom-like dark energy.

Best-fit parameters are consistent with observational data.

Effective Newton's constant evolves over cosmic time.

Abstract

In this paper, the holographic dark energy in Brans-Dicke theory is confronted by cosmic observations from SN Ia, BAO and CMB shift parameter. The best fit parameters are found in $1\sigma$ region: $\Omega_{h0}=0.683^{+0.035}_{-0.038}$, $c=0.605^{+0.138}_{-0.107}$ and $\alpha=0.00662^{+0.00477}_{-0.00467}$ (equivalently $\omega=905.690^{+637.906}_{-651.471}$ which is less the solar system bound and consistent with other constraint results). With these best fit values of the parameters, it is found the universe is undergoing accelerated expansion, and the current value of equation of state of holographic dark energy $w_{h0}=-1.246^{+0.191}_{-0.144}$ which is phantom like in Brans-Dicke theory. The evolution of effective Newton's constant is also explored.