Observational constraints on the equation of state of viscous fluid in f(R,T) gravity
Koussour M. Altaibayeva A. Bekov S. Donmez O. Muminov S. Rayimbaev J.
December 2024Elsevier B.V.
Physics of the Dark Universe
2024#46
In this paper, we investigate a cosmological model based on viscous f(R,T) gravity as a potential alternative to dark energy. This model incorporates bulk viscosity and is analyzed using an effective equation of state. We consider the simplest specific model, f(R,T)=R+λT, where λ is a constant. The exact solution of our viscous f(R,T) cosmological model is derived, and then we use the combined datasets consisting of 31 H(z) data points and 1701 Pantheon+ SNe data points to determine the best-fit values of the model parameters. We find good agreement with observations, particularly at higher redshifts. Our models behavior, including energy density, pressure with viscosity, effective equation of state, and deceleration parameter, is analyzed. It indicates a shift from decelerated to accelerated phases of the universes expansion, suggesting that bulk viscosity in the cosmic fluid could effectively generate the negative pressure necessary for cosmic expansion. Finally, we explore statefinder diagnostics to differentiate between various dark energy models, revealing that our model resides in the quintessence region.
Bulk viscosity , Dark energy , f(R, T) gravity , Observational constraints
Text of the article Перейти на текст статьи
Department of Physics, University of Hassan II Casablanca, Morocco
Department of General and Theoretical Physics, L.N. Gumilyov Eurasian National University, Astana, 010008, Kazakhstan
Kozybayev University, Petropavlovsk, 150000, Kazakhstan
College of Engineering and Technology, American University of the Middle East, Egaila, 54200, Kuwait
Urgench State University, Kh. Alimjan str. 14, Urgench, 221100, Uzbekistan
University of Tashkent for Applied Sciences, Gavhar Str. 1, Tashkent, 100149, Uzbekistan
National University of Uzbekistan, Tashkent, 100174, Uzbekistan
Department of Physics
Department of General and Theoretical Physics
Kozybayev University
College of Engineering and Technology
Urgench State University
University of Tashkent for Applied Sciences
National University of Uzbekistan
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026