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

TL;DR

This paper explores single-field inflation models that predict large curvature perturbations at small scales, highlighting how specific potential shapes can produce significant peaks in the power spectrum.

Contribution

It demonstrates that double-well and running mass potentials can generate large amplitude peaks in the curvature power spectrum at small scales.

Findings

Double-well potentials can produce peaks with amplitude ~0.1.

Running mass models with positive n' around 0.005 predict similar spectrum amplitudes.

Quantum diffusion effects during inflation are estimated for these 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 ~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', 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.