Interacting Ghost Dark Energy in Brans-Dicke Theory

TL;DR

This paper explores the behavior of ghost dark energy within Brans-Dicke cosmology, showing that the equation of state can cross the phantom line and that interactions facilitate this transition.

Contribution

It introduces a novel analysis of ghost dark energy in Brans-Dicke theory, including both interacting and non-interacting cases, highlighting conditions for crossing the phantom divide.

Findings

EoS parameter can cross w=-1 in non-interacting case

Interactions make phantom crossing easier in Brans-Dicke framework

Transition to phantom regime is more feasible than in Einstein gravity

Abstract

We investigate the QCD ghost model of dark energy in the framework of Brans-Dicke cosmology. First, we study the non-interacting ghost dark energy in a flat Brans-Dicke theory. In this case we obtain the EoS and the deceleration parameters and a differential equation governing the evolution of ghost energy density. Interestingly enough, we find that the EoS parameter of the non-interacting ghost dark energy can cross the phantom line ($w_D=-1$) provided the parameters of the model are chosen suitably. Then, we generalize the study to the interacting ghost dark energy in both flat and non-flat Brans-Dicke framework and find out that the transition of $w_D$ to phantom regime can be more easily achieved for than when resort to the Einstein field equations is made.