Varying alpha and cosmic acceleration in Brans-Dicke-BSBM theory: stability analysis and observational tests

TL;DR

This paper combines generalized BSBM and Brans-Dicke models to analyze the variation of the fine structure constant and cosmic acceleration, using stability analysis and observational data to constrain and test the model's predictions.

Contribution

It develops a new theoretical framework integrating BSBM and Brans-Dicke models, and performs stability and observational analyses to explore fine structure constant variation and cosmic acceleration.

Findings

Model confirms current cosmic acceleration.

Predicts significant fine structure constant variation at high redshift.

Identifies attractor solutions in phase space.

Abstract

By integration of generalized BSBM and Brans-Dicke cosmological models, in this article, we investigate the theoretical framework of fine structure constant variation and current cosmic acceleration. We first develop a mathematical formalism to analyse the stability of the model. By employing observational data to constrain the model parameters, phase space is performed and the attractor solutions of the model are detected. We then examine the model against observational data such as observational Hubble parameter dataset and quasar absorption spectra. The results confirms current universe acceleration and also predicts fine structure constant variation. Furthermore, extrapolation of the best fitted model in high redshift ($z> 15$) illustrates a significantly larger variation of fine structure constant in earlier epoch of the universe.