Cosmological evolution in<i> f</i> (R,<i> Lm,</i><i> T)</i> gravity with viscosity

Myrzakulov Y., Koussour M., Muminov S., Ibragimov I., Çalışkan A., Güdekli E., ...More

ANNALS OF PHYSICS, vol.481, 2025 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 481
  • Publication Date: 2025
  • Doi Number: 10.1016/j.aop.2025.170162
  • Journal Name: ANNALS OF PHYSICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, INSPEC, zbMATH
  • Keywords: And observational constraints, Deceleration parameter, Equation of state, f(R, Lm, T) gravity, Viscosity
  • Istanbul University Affiliated: Yes

Abstract

We investigate the cosmological evolution of f(R, Lm,T) gravity, a theory that unifies f(R,T) and f(R,L-m) by considering a gravitational Lagrangian depending on the Ricci scalar R, the matter Lagrangian Lm, and the trace T of the energy-momentum tensor. Focusing on the linear model f (R, L-m, T) = R + alpha L-m + /beta T and introducing a bulk viscous pressure p = -3 zeta H, we constrain the model using cosmic chronometers, PantheonPlus+SH0ES, and BAO datasets. We analyze the evolution of H(z), q(z), rho(z), and omega(z), finding a transition from deceleration to acceleration around zt similar to 1, and a shift from matter-like to dark energy-like behavior at low redshifts. The Om(z) diagnostic reveals deviations from yCDM, confirming a quintessence-like behavior. Our results highlight that viscosity and non-minimal couplings offer a viable mechanism for explaining the late-time acceleration of the universe.