A Transition Model in f(R,T) Theory via Observational Constraints

A particular form of the time-dependent deceleration parameter is used to examine the accelerated expansion of the universe and the phase transition in this expansion in the context of f(R,T) gravity theory for the flat FRW model. The modified field equations are solved under the choice of f(R,T)=R+2f(T). The best fit values of the model parameters that would be consistent with the recent observational datasets that are estimated. For this estimation, 57 points from Cosmic Chronometers (CC) datasets and 1048 points from Pantheon supernovae datasets are used. Bayesian analysis and likelihood function are applied together with Markov Chain Monte Carlo (MCMC) method at 1s and 2s confidence levels. Then, the physical behavior of parameters such as density, pressure and cosmographic parameters corresponding to these constrained values of the model parameters are analyzed. Looking at the deceleration parameter, it is seen that the universe has passed from a decelerating expansion phase to an accelerating phase. As a result, it has been shown that the cosmological model f(R,T) that we discussed can explain the accelerating expansion of the late universe well without resorting to any dark energy component in the energy-momentum tensor.

Automated summary

In this study, a specific form of the time-dependent deceleration parameter is used to examine the accelerated expansion and phase transition in the flat FRW model of the universe within the context of f(R,T) gravity theory. The modified field equations are solved for a choice of f(R,T) = R+2f(T). The best fit values for the model parameters are determined using recent observational datasets, including 57 points from Cosmic Chronometers (CC) datasets and 1048 points from Pantheon supernovae datasets. Bayesian analysis and likelihood function, together with Markov Chain Monte Carlo (MCMC) method, are applied at 1s and 2s confidence levels. The physical behavior of parameters, such as density, pressure, and cosmographic parameters, corresponding to the constrained values of the model parameters, is then analyzed. Looking at the deceleration parameter, it is observed that the universe has transitioned from a decelerating expansion phase to an accelerating phase. Therefore, the cosmological model f(R,T) discussed in this study can successfully explain the accelerating expansion of the late universe without resorting to any dark energy component in the energy-momentum tensor.