Non-Linearly Interacting Ghost Dark Energy in Brans-Dicke Cosmology

TL;DR

This paper explores a non-linear interaction in ghost dark energy within Brans-Dicke cosmology, showing it can address the coincidence problem and produce stable models that resemble Lambda-CDM.

Contribution

It introduces a general non-linear interaction term in ghost dark energy and analyzes its effects on cosmic evolution and stability, which was not previously studied.

Findings

Universe transitions from deceleration to acceleration at z~0.8.

Positive squared sound speed achieved in one non-linear interaction class.

Model approaches but does not fully reach Lambda-CDM behavior.

Abstract

In this paper we extend the form of interaction term into the non-linear regime in the ghost dark energy model. A general form of non-linear interaction term is presented and cosmic dynamic equations are obtained. Next, the model is detailed for two special choice of the non-linear interaction term. According to this the universe transits at suitable time ($z\sim 0.8$) from deceleration to acceleration phase which alleviate the coincidence problem. Squared sound speed analysis revealed that for one class of non-linear interaction term $v_s^2$ can gets positive. This point is an impact of the non-linear interaction term and we never find such behavior in non interacting and linearly interacting ghost dark energy models. Also statefinder parameters are introduced for this model and we found that for one class the model meets the $\Lambda CDM$ while in the second choice although the model approaches the $\Lambda CDM$ but never touch that.