Resolving the Planck-DESI tension by non-minimally coupled quintessence

Abstract

The Planck measurement of cosmic microwave background (CMB) has established the $Λ$-cold-dark-matter ($Λ$CDM) model as the concordant model along with other observations. However, recent measurements of baryon acoustic oscillations (BAO) from Dark Energy Spectroscopic Instrument (DESI) have renewed the matter fraction $Ω_\mathrm{m}$ tension between Planck-$Λ$CDM and DESI-$Λ$CDM. Directly reconciling this CMB-BAO tension with a dynamical DE in Chevallier-Polarski-Linder (CPL) parametrization seems to imply a crossing of the equation-of-state (EoS) through $w=-1$ at low redshifts. In this letter, we resolve this $Ω_\mathrm{m}$ tension by allowing for the DM non-minimally coupled to gravity via a quintessence field. This non-minimal coupling is preferred over $3σ$ confidence level. Consequently, even though the usual effective EoS of the coupled quintessence apart from the standard CDM part never crosses but always above $w=-1$, a misidentification with the $w_0w_a$CDM model would exactly fake such a crossing behavior, and the tensions on neutrino mass and growth rate in the $Λ$CDM model are also relieved in our model as a result of the resolved $Ω_\mathrm{m}$ tension.

Figures (9)

• Figure 1: Cosmological constraints on $\Omega_\mathrm{m}$ and $H_0r_d$ in $w_0w_a$CDM (dotted) and NMCQ (solid) models from Planck CMB, DESI BAO, and DESY5 SNe, separately.
• Figure 2: Cosmological constraints on neutrino mass in $\Lambda$CDM (orange), $w_0w_a$CDM (green), and NMCQ (blue) models from Planck CMB+DESI BAO+DESY5 SNe, and the bounds from the KATRIN experiment for normal ordering (light gray) and inverted ordering (gray) Esteban:2024eli.
• Figure 3: The theoretical predictions on $f\sigma_8$ from NMCQ (blue), $w_0w_a$CDM (orange), and $\Lambda$CDM (gray line), along with observational measurements (gray points). The parameters for each model's prediction are the best-fit constraints from CMB+BAO+SN, except for $\Lambda$CDM (CMB), which uses CMB only. The inset table presents the $\chi^2$ tests obtained with respect to the $f\sigma_8$ data alone for each model.
• Figure 4: Energy densities and EoS parameters for the effective DE $\rho_\mathrm{DE}^\mathrm{eff}$, the apparent DE $\rho_\mathrm{DE}^\mathrm{app}$ (seen by $w_0w_a$CDM model), the quintessence field $\rho_\varphi$, the would-be CDM part $\rho_{\mathrm{DM},0}a^{-3}$, and the non-cold DM part $\Delta\rho_\mathrm{DM}$. The dashed curve for the apparent DE presents its negative value, and vertical lines correspond to the redshifts where $w_\mathrm{DE}^\mathrm{app}=-1$ and $\rho_\mathrm{DE}^\mathrm{eff}=0$.
• Figure 5: The evolution of $\varphi$ during $10^9\leq z<10^{12}$, where the solution with narrowed and enlarged $\varphi_{\mathrm{r},0}$ are separately presented with orange and green dashed lines, and the blue solid line is for the attractor solution. The overlapping between the blue and orange curves arises from the quite rapid increase of $\varphi$ in the very early Universe.