Features of the inflaton potential and the power spectrum of cosmological perturbations

We discuss features of the inflaton potential that can lead to a strong enhancement power spectrum curvature perturbations. show steep decrease induces an by several orders magnitude, which may production primordial black holes. The same feature also create distinctive oscillatory pattern in gravitational waves generated through scalar perturbations at second order. study additive effect such features. analyse simplified potential, but possible application supergravity models.