New Agegraphic Dark Energy in Brans-Dicke Theory

TL;DR

This paper explores the behavior of new agegraphic dark energy within Brans-Dicke theory, revealing its quintom-like evolution and comparing it to Einstein's theory, including cases with interaction.

Contribution

It introduces a new agegraphic dark energy model in Brans-Dicke theory and analyzes its dynamic properties and differences from Einstein's framework.

Findings

Dark energy exhibits quintom-like behavior with equation of state crossing -1

Derived the equation of state and deceleration parameter in Brans-Dicke theory

Compared dark energy behavior in Brans-Dicke and Einstein's theories

Abstract

In this paper, we investigate the new agegraphic dark energy model in the framework of Brans-Dicke theory which is a natural extension of the Einstein's general relativity. In this framework the form of the new agegraphic dark energy density takes as $\rho_{q} =3n^2 \Phi(t)\eta^{-2}$, where $\eta$ is the conformal age of the universe and $\Phi(t)$ is the Brans-Dicke scalar field representing the inverse of the time-variable Newton's constant. We derive the equation of state of the new agegraphic dark energy and the deceleration parameter of the universe in the Brans-Dicke theory. It is very interesting to find that in the Brans-Dicke theory the agegraphic dark energy realizes quintom-like behavior, i.e., its equation of state crosses the phantom divide $w=-1$ during the evolution. We also compare the situation of the agegraphic dark energy model in the Brans-Dicke theory with that in the Einstein's theory. In addition, we discuss the new agegraphic dark energy model with interaction in the framework of the Brans-Dicke theory.