Testing AdS early dark energy with Planck, SPTpol and LSS data

TL;DR

This paper tests the AdS-EDE model, which introduces an Anti-de Sitter phase to early dark energy, using CMB and LSS data to address the Hubble tension and find compatible H_0 values.

Contribution

It provides the first comprehensive test of the AdS-EDE model with combined CMB and LSS data, showing its potential to resolve the Hubble tension.

Findings

Best-fit H_0 without SH0ES prior: 71.92 km/s/Mpc

Best-fit H_0 with SH0ES prior: 73.29 km/s/Mpc

Discrepancy in S_8 reduced to 1.3 sigma

Abstract

The Hubble tension might be resolved by injecting a new energy component, called Early Dark Energy (EDE), prior to recombination. An Anti-de Sitter (AdS) phase around recombination can make the injected energy decay faster, which thus allows a higher EDE fraction (so larger $H_0$) while prevents degrading the CMB fit. In this work, we test the AdS-EDE model with CMB and Large-Scale Structure (LSS) data. Our CMB dataset consists of low-$\ell$ part of Planck TT spectrum and SPTpol polarization and lensing measurements, since this dataset predicts the CMB lensing effect consistent with $\Lambda$CDM expectation. Combining it with BAO and Pantheon data, we find the bestfit values $H_0=71.92$ km/s/Mpc and $H_0=73.29$ km/s/Mpc without and with the SH0ES prior, respectively. Including cosmic shear and galaxy clusters data, we have $H_0=71.87$ km/s/Mpc and $S_8=0.785$, i.e. only $1.3\sigma$ discrepancy with direct $S_8$ measurement.