New limits on Early Dark Energy from the South Pole Telescope

TL;DR

This paper provides new, tighter constraints on early dark energy density using combined data from WMAP and South Pole Telescope, improving previous limits and analyzing the role of small-scale CMB anisotropies.

Contribution

The study offers the first strong upper limit on EDE density from combined CMB data and explains how small-scale anisotropies constrain EDE.

Findings

EDE density Omega_e < 0.018 at 95% confidence

Adding low-redshift probes does not improve EDE constraints

Small-scale CMB anisotropies significantly constrain EDE

Abstract

We present new limits on early dark energy (EDE) from the cosmic microwave background (CMB) using data from the WMAP satellite on large angular scales and South Pole Telescope (SPT) on small angular scales. We find a strong upper limit on the EDE density of Omega_e < 0.018 at 95% confidence, a factor of three improvement over WMAP data alone. We show that adding lower-redshift probes of the expansion rate to the CMB data improves constraints on the dark energy equation of state, but not the EDE density. We also explain how the small-scale CMB temperature anisotropy constrains EDE.