Bulk viscous matter in f(T) gravity: A path to cosmic acceleration
Myrzakulov K. Donmez O. Koussour M. Muminov S. Davletov E. Rayimbaev J.
28 February 2025Elsevier B.V.
Physics Letters, Section A: General, Atomic and Solid State Physics
2025#534
In this paper, we investigate the effects of varying bulk viscosity coefficients ζ(t)=ζ0+ζ1H on cosmic evolution within the framework of f(T) teleparallel gravity. We focus on two cases: (i) ζ1≠0 and (ii) ζ1=0, deriving the Hubble parameter H as a function of redshift z using a linear f(T) model (f(T)=αT where α≠0). Using the combined H(z)+Pantheon++BAO dataset, we obtain observational constraints on model parameters. For Case I (ζ1≠0), best-fit values are H0=60.0−1.9+2.0 km/s/Mpc, α=1.01−0.098+0.10, ζ0=40.1−2.0+1.9, and ζ1=0.123−0.088+0.093, while for Case II (ζ1=0), they are H0=67.5−1.3+1.3 km/s/Mpc, α=0.94−0.13+0.14, and ζ0=34.7−2.0+2.0. The analysis reveals a transition in the deceleration parameter, indicating a shift from deceleration to acceleration of the universes expansion, with present-day values of q0≈−0.49 and q0≈−0.32 for the respective cases. The jerk parameter j(z) and effective EoS for the cosmic viscous fluid also support the cosmic acceleration, with trajectories aligning with the quintessence scenario. These findings underscore the potential of our f(T) model dominated by bulk viscous matter in explaining cosmic acceleration.
Bulk viscosity , f(T) teleparallel gravity , Om(z) diagnostic , Statefinder parameters
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Department of General & Theoretical Physics, L.N. Gumilyov Eurasian National University, Astana, 010008, Kazakhstan
College of Engineering and Technology, American University of the Middle East, Egaila, 54200, Kuwait
Department of Physics, University of Hassan II Casablanca, Morocco
Mamun University, Bolkhovuz Street 2, Khiva, 220900, Uzbekistan
Institute of Fundamental and Applied Research, National Research University TIIAME, Kori Niyoziy 39, Tashkent, 100000, Uzbekistan
University of Tashkent for Applied Sciences, Str. Gavhar 1, Tashkent, 100149, Uzbekistan
Urgench State University, Kh. Alimjan Str. 14, Urgench, 221100, Uzbekistan
Shahrisabz State Pedagogical Institute, Shahrisabz Str. 10, Shahrisabz, 181301, Uzbekistan
Department of General & Theoretical Physics
College of Engineering and Technology
Department of Physics
Mamun University
Institute of Fundamental and Applied Research
University of Tashkent for Applied Sciences
Urgench State University
Shahrisabz State Pedagogical Institute
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