Perfect fluid dynamics with observational constraint in the framework of f(T) gravity

In this study, we explore cosmological models within the framework of f(T) gravity by utilizing the energy–momentum tensor for a perfect fluid to solve the corresponding field equations. We derive key cosmological parameters, including the Hubble parameter H. Parameter constraints were applied using the R2 test, resulting in best-fit values of β=108.51−0.40+0.41 and ξ1=−0.14717−0.00096+0.00094, with a strong alignment with the ΛCDM model (R2=0.9280; RMSE = 11.4068). The deceleration parameter, calculated in terms of cosmic time and redshift, indicates a transition from deceleration to acceleration, consistent with current observations of an accelerating universe. Additionally, we examined the pressure p, energy density ρ, and equation of state parameter ω for two specific models: Model-I for f(T)=λT and Model-II for f(T)=T+βT2. The Om diagnostic plotted against redshift for ξ1 shows that Ω(z) stabilizes around 0.3 after a slight deviation at z≈0, with a narrow uncertainty band. The model closely aligns with ΛCDM at higher redshifts. The pair of statefinder diagnostics r vs. s is also discussed, and our model for (r,s)=(1,0) represents the ΛCDM model. © 2025