Observational Constraints on Noncoincident $f(Q)$-Gravity with Matter-Gravity Coupling

Abstract

We investigate $f\left( Q\right) $-gravity with a matter-gravity coupling as a geometric dark energy candidate for the description of the late-time cosmic acceleration within a spatially flat Friedmann--Lemaître-Robertson-Walker geometry. We select a noncoincident connection that naturally follows from the general framework of cosmological models with nonzero spatial curvature. We present observational constraints for the simplest $f\left( Q\right) =f_{0}Q^{n}$ model using data from Supernovae, Baryon Acoustic Oscillations and Cosmic Chronometers. For different data combinations we found consistent constraints, with a best-fit value for the power-law index $n\simeq2$. A comparison with the $Λ$CDM model shows that the $f\left( Q\right) $-gravity leads to larger values for the likelihood, while Akaike's Information Criterion suggests statistical equivalence between the two models for most data combinations.

Figures (8)

• Figure 1: Confidence regions of the numerical results of the non-coincidence $f\left( Q\right)$-gravity as derived from the datasets $D_{1}:PP\&BAO$ and $D_{4}:PP\&OHD\&BAO$.
• Figure 2: Confidence regions of the numerical results of the non-coincidence $f\left( Q\right)$-gravity as derived from the datasets $D_{2}:U3\&BAO$ and $D_{5}:U3\&OHD\&BAO$.
• Figure 3: Confidence regions of the numerical results of the non-coincidence $f\left( Q\right)$-gravity as derived from the datasets $D_{3}:DD\&BAO$ and $D_{6}:DD\&OHD\&BAO$.
• Figure 4: Parameter space showing the dynamical evolution of the Hubble function $H\left( z\right)$, the deceleration parameter $q\left( z\right)$, effective dark energy density $\Omega_{DE}\left( z\right)$, the kinetic term of the scalar field $x_{\phi}\left( z\right)$, the connection component $x_{\Psi }\left( z\right)$ and variable $y\left( z\right)$, for the parameter values with the 68% credible intervals derived from the observational constraints of dataset $D_{4}.$
• Figure 5: Parameter space showing the dynamical evolution of the Hubble function $H\left( z\right)$, the deceleration parameter $q\left( z\right)$, effective dark energy density $\Omega_{DE}\left( z\right)$, the kinetic term of the scalar field $x_{\phi}\left( z\right)$, the connection component $x_{\Psi }\left( z\right)$ and variable $y\left( z\right)$, for the parameter values within the 68% credible intervals derived derived from the observational constraints of dataset $D_{5}.$