Cosmic evolution of the logarithmic f(R) model and the dS swampland conjecture

In this paper, we study the inflationary scenario in logarithmic f(R) gravity, where the rate of inflation roll is constant. On the other hand, our gravitational f(R) model is a polynomial plus a logarithmic term. We take advantage of constant-roll conditions and investigate the cosmic evolution of the logarithmic f(R) gravity. Therefore, we plot some figures such as the scalar spectrum index $n_{s}$ and tensor-to-scaler ratio $r$ concerning $n$, $\beta$ and model's constant parameters, i.e., $\alpha$, $\theta$ and $\gamma$ respectively. Also, we obtain the potential by using the constant roll condition. We know that the potential value obtained with this condition has an exact value. Next, we challenge it with refined swampland conjecture with respect to the Planck data. Finally, we compare our results with the experimental data, especially Planck 2018.