Searching for Early Dark Energy beyond Planck and SH0ES

by Dr Vivian Poulin (Montpellier U.)

Thursday 7 Apr 2022, 12:00 → 13:00 Europe/Madrid

Seminar Room (IFAE)

The Hubble tension is a well-known discrepancy between the $\Lambda$CDM prediction of the Hubble constant calibrated on Planck and its direct estimate through the cosmic distance ladder by the SH0ES collaboration. One of the model suggested to resolve this tension involves the presence of `early dark energy’, a dark energy-like component at time prior to recombination (often toy-modeled by a scalar-field with a modified axion potential). In this talk, after briefly reviewing the rapidly evolving state of the Hubble tension, and giving theoretical guidelines to resolving the tension, I will present the latest constraints on EDE as a resolution to the Hubble tension. I will in particular discuss constraints — and hints of detection —  from data beyond the standard `Planck+SH0ES analyses. I will show that on the one hand the recent ACT data and Planck polarization data show hints of the presence of EDE (at the 2.5-3sigma level), while Planck temperature favor LCDM, although the discrepancy stays compatible with a statistical fluctuation. Additionally, I will discuss implications of the EDE for large-scale structures, in particular a new analysis of BOSS-DR12 data though the effective field theory of large-scale structure, showing that  BOSS-DR12 data do not (yet) place strong constraints on EDE. Finally, I will discuss the impact of EDE for the `S8 tension’, the discrepancy between the prediction of the amplitude of fluctuations on 8Mpc/h scales in $\Lambda$CDM and the measurements from weak lensing surveys. I will briefly discuss potential models that could resolve the S8 tension while leaving the EDE resolution unaffected, as a proof-of-principle that solutions to current cosmic tensions may live in different (dark) sectors, or at least points towards different new properties of the same (dark) sector.

Zoom link: https://us02web.zoom.us/j/89787514064?pwd=SkRaOElqanZRNFZXM2d2SE9PN1d0Zz09