Probing dark energy beyond $z=2$ with CODEX

TL;DR

This paper discusses how the CODEX spectrograph can measure fundamental couplings and redshift drift to explore dark energy models beyond redshift 2, providing new insights into the universe's expansion history.

Contribution

It demonstrates the potential of CODEX to probe dynamical dark energy models using measurements of fundamental couplings and redshift drift at high redshifts.

Findings

CODEX can measure the behavior of dark energy's equation of state beyond redshift 2.

It enables testing of dynamical dark energy models deep in the matter era.

The approach distinguishes certain models from the standard $\\Lambda$CDM paradigm.

Abstract

Precision measurements of nature's fundamental couplings and a first measurement of the cosmological redshift drift are two of the key targets for future high-resolution ultra-stable spectrographs such as CODEX. Being able to do both gives CODEX a unique advantage, allowing it to probe dynamical dark energy models (by measuring the behavior of their equation of state) deep in the matter era and thereby testing classes of models that would otherwise be difficult to distinguish from the standard $\Lambda$CDM paradigm. We illustrate this point with two simple case studies.