High energy description of dark energy in an approximate 3-brane Brans-Dicke cosmology

TL;DR

This paper explores a five-dimensional Brans-Dicke cosmology, deriving a modified wave equation and demonstrating that at high energies, it can mimic standard cosmology with an adjusted equation of state, aligning with dark energy observations.

Contribution

It introduces a high-energy approximation of 3-brane Brans-Dicke cosmology and shows its consistency with observed dark energy data.

Findings

High energy limit simplifies the cosmology to a standard form

Dark energy component matches observational data

Modified wave equation derived for Brans-Dicke field

Abstract

We consider a Brans-Dicke cosmology in five-dimensional space-time. Neglecting the quadratic and the mixed Brans-Dicke terms in the Einstein equation, we derive a modified wave equation of the Brans-Dicke field. We show that, at high energy limit, the 3-brane Brans-Dicke cosmology could be described as the standard one by changing the equation of state. Finally as an illustration of the purpose, we show that the dark energy component of the universe agrees with the observations data.