Late-time cosmological evolution in f(R,ℒm) gravity with a matter-dominated background
International Journal of Geometric Methods in Modern Physics, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1142/s0219887826502592
- Dergi Adı: International Journal of Geometric Methods in Modern Physics
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, MathSciNet, zbMATH, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO), Technology Collection (ProQuest)
- Anahtar Kelimeler: cosmic acceleration, Matter field, MCMC techniques
- İstanbul Üniversitesi Adresli: Evet
Özet
This study explores the late-time accelerated expansion of the universe and the evolution of cosmic structures in the context of a particular f(R,ℒm) gravity model — an extended gravitational framework in which the standard Einstein–Hilbert action is generalized by incorporating a nonlinear coupling between spacetime curvature and matter fields. The specific form of the gravitational action is chosen as f(R,ℒm) = R/2 + ℒmn − β, where n and β are free model parameters, and the corresponding equations of motion are derived assuming a matter-dominated cosmological condition. The study is formulated for a spatially flat FLRW universe, where we derive an exact analytical solution to the field equations. We constrain the model parameters using advanced Markov Chain Monte Carlo techniques, employing a combined dataset of BAO, cosmic chronometers, and standard candles. Furthermore, we examine the behavior of physical parameters that describe the various phases of cosmic evolution, including the deceleration parameter q, jerk j, and snap s parameters and also the statefinder pairs (s,r) and (q,r). We determine the transition redshift at which the cosmic expansion shifts from decelerating to accelerating, with a resulting value of ztr = 0.652. Statefinder diagnostics show that the f(R,ℒm) model follows a simple trajectory, lies in the quintessence region. These findings underscore the significance of f(R,ℒm) gravity in explaining cosmic acceleration, without requiring a cosmological constant, and offering a promising framework for future explorations of dark energy and the evolution of the universe.