Is there further evidence for spatial variation of fundamental constants?

TL;DR

This paper investigates potential spatial variations of fundamental constants like alpha and mu during the early universe and analyzes existing astrophysical data for signs of such variations, finding only weak indications.

Contribution

It proposes a new method to test for spatial variation of constants during big bang nucleosynthesis and analyzes existing data for evidence of such variations.

Findings

Weak indications of alpha variation during nucleosynthesis

No definitive evidence for spatial variation of mu or related constants

Highlights the need for more measurements to confirm potential variations

Abstract

The detection of a spatial variation of the fine-structure constant, alpha, based on study of quasar absorption systems has recently been reported. The physics that causes this alpha-variation should have other observable manifestations, and this motivates us to look for complementary astrophysical effects. In this paper we propose a method to test whether spatial variation of fundamental constants existed during the epoch of big bang nucleosynthesis. Using existing measurements of primordial deuterium abundance we find very weak indications that such a signature might exist, but the paucity of measurements precludes any firm conclusion. We also examine existing quasar absorption spectra data that are sensitive to variation of the electron-to-proton mass ratio, mu, and x = (alpha^2 mu g_p) for spatial variation.