Swampland Criteria and Constraints on Inflation in a $f(R,T)$ Gravity Theory

Abstract: In this paper, we worked in the framework of an inflationary $f(R,T)$ theory, in the presence of a canonical scalar field. More specifically, the $f(R,T)=\gamma R+2\kappa\alpha T$ gravity. The values of the dimensionless parameters $\alpha$ and $\gamma$ are taken to be $\alpha \geq 0$ and $0 < \gamma \leq 1$. The motivation for that study was the striking similarities between the slow-roll parameters of the inflationary model used in this work and the ones obtained by the rescaled Einstein-Hilbert gravity inflation $f(R)=\alpha R$. We examined a variety of potentials to determine if they agree with the current Planck Constraints. In addition, we checked whether these models satisfy the Swampland Criteria and we specified the exact region of the parameter space that produces viable results for each model. As we mention in Section IV the inflationary $f(R,T)$ theory used in this work can not produce a positive $n_T$ which implies that the stochastic gravitational wave background will not be detectable.