Large curvature perturbations near horizon crossing in single-field inflation models

Abstract

We consider the examples of single-field inflation models predicting large amplitudes of the curvature perturbation power spectrum at relatively small scales. It is shown that in models with an inflationary potential of double-well type the peaks in the power spectrum, having, in maximum, the amplitude ${\mathcal{P}}_{\mathcal{R}}\ensuremath{\sim}0.1$, can exist (if parameters of the potential are chosen appropriately). It is shown also that the spectrum amplitude of the same magnitude (at large $k$ values) is predicted in the model with the running mass potential, if the positive running, ${n}^{\ensuremath{'}}$, exists and is about 0.005 at cosmological scales. Estimates of the quantum diffusion effects during inflation in models with the running mass potential are given.