Exponential $f(R)$ cosmology with massive neutrinos as a dynamical dark energy framework

Abstract

The exponential $f(R)$ gravity model provides a theoretically well-motivated extension of General Relativity, introducing a modified gravitational dynamics at late times consistent with a dynamical dark energy scenario, while recovering the $Λ$CDM-like regime at high redshifts with a smooth transition. Using a Bayesian Markov Chain Monte Carlo (MCMC) analysis, we constrain the parameters of the exponential $f(R)$ model in combination with the total neutrino mass $\sum m_ν$, employing the latest measurements from cosmic chronometers, the DESI DR2 BAO data, the CMB acoustic scale, and the Pantheon+ supernovae compilation, comparing the results with the $Λ$CDM and the $w_0w_a$CDM models. Our results show that the exponential $f(R)$ model remains consistent with current observations while slightly alleviating the Hubble tension and the neutrino mass problem relative to $Λ$CDM, although the constraints on $\sum m_ν$ are tighter than those obtained for the phenomenological $w_0w_a$CDM scenario. These results indicate that the interplay between modified gravity and neutrino physics in the late Universe may offer a viable framework for further investigation of cosmological tensions.