The variation of the gravitational constant inferred from the Hubble diagram of Type Ia supernovae

TL;DR

This paper investigates a cosmological model with a variable gravitational constant G, derived from scalar-tensor theory, using supernova data to describe G's variation and its implications for fundamental constants.

Contribution

It introduces a phenomenological expression for G's variation based on supernova observations within a scalar-tensor framework.

Findings

G varies over cosmological timescales according to the model

The variation of the fine structure constant lpha does not align with existing constraints

Supernova data can be used to infer changes in fundamental constants

Abstract

We consider a cosmological model with a variable gravitational constant, G, based on a scalar-tensor theory. Using the recent observational data for the Hubble diagram of type Ia supernovae (SNeIa) we find a phenomenological expression describing the variation of G. The corresponding variation of the fine structure constant \alpha within multidimensional theories is also computed and is shown not to support known constraints on \Delta \alpha / \alpha.