Constant-roll brane inflation

The scenario of constant-roll inflation in the frame of the Randall-Sundraum II (RS II) brane gravity model is considered. Based on the scenario, the smallness of the second slow-roll parameter is released and it is assumed as a constant which could be of the order of unity. Applying the Hamilton-Jacobi formalism, the constancy of the parameter gives a differential equation for the Hubble parameter which leads to an exact solution for the model. Reconsidering the perturbation equations, we show there are some modified terms appearing in the amplitude of the scalar perturbations and in turn in the scalar spectral index and tensor-to-scalar ratio. Comparing the theoretical results of the model with observational data, the free parameters of the model are determined. Then, the consistency of the model with the swampland criteria is investigated for the obtained values of the free parameters. As the final step, the attractor behavior of the model is considered.