Testing H0 in Acoustic Dark Energy Models with Planck and ACT Polarization

TL;DR

This paper tests the canonical acoustic dark energy (cADE) model against Planck and ACT polarization data, showing it can alleviate the Hubble tension and is increasingly constrained by improved polarization measurements, distinguishing it from other models.

Contribution

It provides new constraints on the cADE model using recent CMB polarization data, demonstrating its viability in addressing the Hubble tension and distinguishing it from other early dark energy models.

Findings

cADE model fits well with ACT and Planck data

Best-fit H0 in cADE is higher than in ΛCDM

Improved polarization data constrains cADE and distinguishes it from other models

Abstract

The canonical acoustic dark energy model (cADE), which is based on a scalar field with a canonical kinetic term that rapidly converts potential to kinetic energy around matter radiation equality, alleviates the Hubble tension found in $\Lambda$CDM. We show that it successfully passes new consistency tests in the CMB damping tail provided by the ACT data, while being increasingly constrained and distinguished from alternate mechanisms by the improved CMB acoustic polarization data from Planck. The best fit cADE model to a suite of cosmological observations, including the SH0ES $H_0$ measurement, has $H_0=70.25$ compared with $68.23$ (km s$^{-1}$ Mpc$^{-1}$) in $\Lambda$CDM and a finite cADE component is preferred at the $2.8\sigma$ level. The ability to raise $H_0$ is now mainly constrained by the improved Planck acoustic polarization data, which also plays a crucial role in distinguishing cADE from the wider class of early dark energy models. ACT and Planck TE polarization data are currently mildly discrepant in normalization and drive correspondingly different preferences in parameters. Improved constraints on intermediate scale polarization approaching the cosmic variance limit will be an incisive test of the acoustic dynamics of these models and their alternatives.