Speaker
Description
It is found that the DESI observation can be explained by non-minimal coupled gravity. In this talk I will show that the resulting non-minimally coupled scalar-tensor gravity theory, Thawing Gravity (TG), also presents a possible resolution to the cosmological tensions. Using the standard Bayes model comparison method, TG has moderate evidence over $\Lambda$CDM with a Bayes factor $\ln B=+1.5$ in the baseline analysis CMB+BAO+SNIa, and strong evidence $\ln B=+11.8$ if the Cepheids calibration of the SNIa distance ladder from SH0ES is taken into consideration in the baseline+SH0ES analysis, yielding $H_0=71.78\pm0.86 \ {\rm km/s/Mpc}$ and $S_8=0.793\pm0.012$. Interestingly, TG predicts a prerecombination Newtonian constant $G_{\rm CMB}$ larger than that of today $G_N$ at $\sim2\sigma$ in the baseline CMB+BAO+SNIa and $4\sigma$ with baseline+$H_0$. The obtained $G_{\rm CMB}/G_N$ is consistent with current BBN constraint and can be tested by future observations. I will also discuss the possible screening mechanism to make TG compatible with solar system constraints.
