Reconstruction of a scalar-tensor theory of gravity in an accelerating universe

TL;DR

This paper demonstrates how to reconstruct a scalar-tensor gravity theory explaining the universe's acceleration using observable cosmological functions, providing explicit results in a specific approximation.

Contribution

It introduces a method to determine the scalar field potential and coupling function from observable data in scalar-tensor gravity models of the accelerating universe.

Findings

Reconstruction of scalar-tensor theory from luminosity distance and density perturbations

Explicit first-order results in inverse Brans-Dicke parameter

Method links observational data to fundamental gravity theory parameters

Abstract

The present acceleration of the Universe strongly indicated by recent observational data can be modeled in the scope of a scalar-tensor theory of gravity. We show that it is possible to determine the structure of this theory (the scalar field potential and the functional form of the scalar-gravity coupling) along with the present density of dustlike matter from the following two observable cosmological functions: the luminosity distance and the linear density perturbation in the dustlike matter component as functions of redshift. Explicit results are presented in the first order in the small inverse Brans-Dicke parameter 1/omega.