Hints of Nonminimally Coupled Gravity in DESI 2024 Baryon Acoustic Oscillation Measurements

Understand

The cosmic microwave background (CMB) and baryon acoustic oscillations (BAO) are two of the most robust observations in cosmology.

• The recent BAO measurements from the DESI collaboration have presented, for the first time, inconsistency between BAO and CMB within the standard cosmological model $\Lambda$CDM, indicating a preference for dynamical dark energy over a cosmological constant.
• We analyze the theoretical implication of the DESI BAO observation for dark energy and gravity employing a nonparametric reconstruction approach for both the dark energy equation of state $w_{\rm DE}(a)$ and the effective field theory coefficients.
• We find that the DESI data can rule out quintessence dark energy by indicating a crossing of the phantom divide at $z\lesssim1$.