Limits on Clustering and Smooth Quintessence from the EFTofLSS

TL;DR

This paper uses the Effective Field Theory of Large-Scale Structure to analyze clustering quintessence models, providing constraints on the equation of state parameter that support a cosmological constant.

Contribution

It extends EFTofLSS to clustering quintessence, computes the one-loop power spectrum, and derives observational constraints on the quintessence equation of state.

Findings

Constraints on w: -1.011_{-0.048}^{+0.053} without Planck

Constraints on w: -1.028_{-0.030}^{+0.037} with Planck

Supports a cosmological constant as the best fit

Abstract

We apply the Effective Field Theory of Large-Scale Structure (EFTofLSS) to analyze cosmological models with clustering quintessence, which allows us to consistently describe the parameter region in which the quintessence equation of state $w < - 1$. First, we extend the description of biased tracers in redshift space to the presence of clustering quintessence, and compute the one-loop power spectrum. We solve the EFTofLSS equations using the exact time dependence, which is relevant to obtain unbiased constraints. Then, fitting the full shape of BOSS pre-reconstructed power spectrum measurements, the BOSS post-reconstruction BAO measurements, BAO measurements from 6DF/MGS and eBOSS, the Supernovae from Pantheon, and a prior from BBN, we bound the clustering quintessence equation of state parameter $w=-1.011_{-0.048}^{+0.053}$ at $68\%$ C.L.. Further combining with Planck, we obtain $w=-1.028_{-0.030}^{+0.037}$ at $68\%$ C.L.. We also obtain constraints on smooth quintessence, in the physical regime $w \geq -1$: combining all datasets, we get $-1\leq w < - 0.979$ at $68\%$ C.L.. These results strongly support a cosmological constant.