Exploration of Parameters in f(R,T) Gravity and Comparison with Type Ia Supernovae Data

The expansion of the Universe in $f(R,T)$ gravity is studied. We consider functions of the form $f(R,T)=R+\lambda T^{\epsilon }$ where $\epsilon <1$. We find that for all models with $\epsilon <0$, the Universe transitions to exponential growth at late times, just as it does in the standard cosmological model, which corresponds to $\epsilon =0$. It also fits the type Ia supernova data slightly better than the standard cosmological model, without increasing the number of parameters of the theory. In contrast, the fits for $\epsilon >0$ rapidly become worse than the standard cosmological model.