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