Dynamical analysis of Brans-Dicke Universe with inverse power-law effective potential

TL;DR

This paper analyzes the dynamics of the Brans-Dicke cosmological model with an inverse power-law potential, identifying stable phases corresponding to radiation, matter, and dark energy dominance, consistent with observational data.

Contribution

It provides a dynamical systems analysis of Brans-Dicke cosmology with a specific potential, revealing stable dark energy solutions and their observational viability.

Findings

Stable dark energy-dominated fixed point identified

Phase space trajectories show transition from matter to dark energy era

Variation of gravitational constant aligns with observations

Abstract

We study Brans-Dicke cosmology with an inverse power-law effective potential. By using dynamical analyses, we search for fixed points corresponding to the radiation-like matter and dark energy-dominated era of our Universe, and the stability of fixed points is also investigated. We find phase space trajectories which are attracted to the stable point of the dark energy-dominated era from unstable fixed points like matter-dominated era of the Universe. The dark energy comes from effective potentials of the Brans-Dicke field, whose variation (related to the time-variation of the gravitational coupling constant) is shown to be in good agreement with observational data.