Interacting holographic dark energy in Brans-Dicke theory

TL;DR

This paper explores how interacting holographic dark energy within Brans-Dicke cosmology can explain the crossing of the equation of state parameter through -1, with implications for cosmic acceleration and dark energy models.

Contribution

It introduces a model combining Brans-Dicke theory with interacting holographic dark energy, demonstrating the crossing of the equation of state parameter and easier phantom regime transition.

Findings

Noninteracting holographic dark energy can achieve w_D = -1 crossing.

Interaction facilitates transition to phantom regime.

Model accommodates cosmic acceleration in non-flat universe.

Abstract

We study cosmological application of interacting holographic energy density in the framework of Brans-Dicke cosmology. We obtain the equation of state and the deceleration parameter of the holographic dark energy in a non-flat universe. As system's IR cutoff we choose the radius of the event horizon measured on the sphere of the horizon, defined as $L=ar(t)$. We find that the combination of Brans-Dicke field and holographic dark energy can accommodate $w_D = -1 $ crossing for the equation of state of \textit{noninteracting} holographic dark energy. When an interaction between dark energy and dark matter is taken into account, the transition of $w_D$ to phantom regime can be more easily accounted for than when resort to the Einstein field equations is made.