Quintessence's Last Stand?

TL;DR

This paper examines the ability of current and future cosmological data to distinguish thawing quintessence models from a cosmological constant, highlighting challenges and potential improvements in detection sensitivity.

Contribution

It analyzes the observational distinguishability of thawing dark energy models from a cosmological constant and discusses how redshift drift data can enhance this capability.

Findings

Deviations from w=-1 are hard to detect with current data.

Next-generation measurements have limited sensitivity to small deviations.

Redshift drift data can double the sensitivity to thawing dark energy models.

Abstract

Current cosmological data puts increasing pressure on models of dark energy in the freezing class, e.g. early dark energy or those with equation of state $w$ substantially different from $-1$. We investigate to what extent data will distinguish the thawing class of quintessence from a cosmological constant. Since thawing dark energy deviates from $w=-1$ only at late times, we find that deviations $1+w\lesssim0.1$ are difficult to see even with next generation measurements; however, modest redshift drift data can improve the sensitivity by a factor of two. Furthermore, technical naturalness prefers specific thawing models.