Varying fundamental constants and dark energy in the ESPRESSO era

TL;DR

This paper reviews recent observational tests of the stability of fundamental constants and explores their implications for dark energy models, highlighting potential improvements with upcoming ELT-HIRES and Euclid data.

Contribution

It provides new observational constraints on fundamental constants across different epochs and forecasts the enhanced sensitivity of future telescopes for testing dark energy models.

Findings

Constraints on fundamental constants at low redshift and BBN epoch.

Implications for quintessence and string-inspired models.

Forecasted sensitivity improvements with ELT-HIRES and Euclid.

Abstract

The observational evidence for the recent acceleration of the universe shows that canonical theories of cosmology and particle physics are incomplete and that new physics is out there, waiting to be discovered. A compelling task for astrophysical facilities is to search for, identify and ultimately characterize this new physics. I present very recent developments in tests of the stability of nature's fundamental constants, as well as their impact on physics paradigms beyond the standard model. Specifically I discuss new observational constraints at low redshifts and at the BBN epoch, and highlight their different implications for canonical quintessence-type models and for non-canonical string-theory inspired models. Finally I also present new forecasts, based on realistic simulated data, of the gains in sensitivity for these constraints expected from ELT-HIRES, on its own and in combination with Euclid.