Late-time acceleration in extended and unified f(R,Lm,T) gravity with observational data
Аннотация
In this paper, we investigate the late-time acceleration of the universe within the extended [Formula: see text] gravity framework, which unifies curvature, matter Lagrangian, and the trace of the energy–momentum tensor in a single gravitational action. Considering the simplest functional form [Formula: see text], we adopt a parametric form of the deceleration parameter [Formula: see text] to reconstruct the Hubble parameter [Formula: see text]. Using Markov Chain Monte Carlo methods with combined observational Hubble data (OHD) and type Ia supernovae (SNe Ia) datasets, we constrain the cosmological parameters [Formula: see text], [Formula: see text], and [Formula: see text], finding [Formula: see text], [Formula: see text], and [Formula: see text]. Our results indicate a current accelerated expansion and a deceleration-to-acceleration transition consistent with observations. The inferred [Formula: see text] value lies between Planck 2018 and local SH0ES measurements, suggesting the parametrization may alleviate the Hubble tension. We further explore the impact of coupling parameters [Formula: see text] and [Formula: see text] on the energy density, pressure, and equation of state parameter [Formula: see text], revealing a quintessence-like dark energy behavior without phantom crossing. These findings demonstrate the versatility of the [Formula: see text] model in explaining cosmic acceleration and provide a promising alternative to the standard [Formula: see text]CDM cosmology.