Divergence-free deceleration and energy conditions in non-minimal f(R,T) gravity
Zhadyranova A. Koussour M. Kanibekova Z. Zhumabekova V. Ismail U. Muminov S. Rayimbaev J.
22 April 2025World Scientific
International Journal of Geometric Methods in Modern Physics
2025#23Issue 2
In this paper, we investigate the divergence-free parametric form of the deceleration parameter within the simplest non-minimal matter-geometry coupling in f(R,T) gravity, where R is the Ricci scalar and T is the trace of the energy–momentum tensor. Specifically, we consider the linear model f(R,T) = R + 2λT, where λ governs the interaction between matter and geometry. Using this parametric form, we derive the Hubble parameter as a function of redshift z and incorporate it into the modified Friedmann equations. Constraining the model with OHD and Pantheon data, we obtain precise estimates for H0, the present deceleration parameter q0, and its evolutionary component q1, confirming a smooth transition between cosmic deceleration and acceleration. Further, we analyze the evolution of the energy density ρ and total EoS parameter ω for different λ values, highlighting deviations from ΛCDM and the role of λ in shaping cosmic dynamics. In addition, we examine energy conditions, finding that the NEC and DEC are satisfied throughout evolution, while the SEC is violated at late times, supporting the observed acceleration. Our findings demonstrate that this divergence-free parameterization within f(R,T) gravity offers a viable framework for explaining late-time cosmic acceleration while maintaining key observational and theoretical constraints.
cosmic acceleration , Divergence-free deceleration , energy conditions , equation of state , f(R,T) gravity , non-minimal coupling , observational constraints
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L. N. Gumilyov Eurasian National University, General and Theoretical Physics Department, Astana, 010008, Kazakhstan
Department of Physics, University of Hassan II, Casablanca, Morocco
Theoretical and Nuclear Physics Department, Al-Farabi Kazakh National University, Almaty, 050040, Kazakhstan
Mamun University, Bolkhovuz Street 2, Khiva, 220900, Uzbekistan
New Uzbekistan University, Movarounnahr Street 1, Tashkent, 100007, Uzbekistan
Urgench State University, Kh. Alimjan Street 14, Urgench, 221100, Uzbekistan
L. N. Gumilyov Eurasian National University
Department of Physics
Theoretical and Nuclear Physics Department
Mamun University
New Uzbekistan University
Urgench State University
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