An updated constraint on the Effective Field Theory of Dark Energy

Abstract: The Effective Field Theory of Dark Energy (EFTofDE) provides a systematic and model-independent framework to study dark energy (DE) and modified gravity (MG) with one additional scalar degree of freedom. It can describe the known models such as Quintessence, k-essence, DGP, $f(R)$, and Horndeski theories. In this work, we update constraints on EFTofDE by utilizing the most up-to-date public data including the BAO (DESI DR2), CMB (Planck 2018 & ACT DR6), SNIa (DESY5), weak lensing (DESY3) and full-shape galaxy power (BOSS DR12). We find with the $\Lambda$CDM background, general relativity (GR) is favored by the data, while with the $w0wa$CDM background, slight modification to GR is favored, but still consistent with GR within $1.5\sigma$. We also find the significance level for dynamical DE is greatly reduced within EFTofDE compared to within GR, indicating the degeneracy between dynamical DE and MG.