# Resonant Reconciliation of Convex Models and the Planck

## TL;DR

This paper proposes a resonant inflationary model with cosine modulations and a light scalar field, which enhances the power spectrum via one-loop effects, helping reconcile convex inflation models with Planck data.

## Contribution

It introduces a resonant mechanism in convex inflation models with cosine couplings, modifying the power spectrum and spectral tilt to align with observational constraints.

## Key findings

- Resonant interactions dominate the curvature perturbation power spectrum.
- The model suppresses tensor-to-scalar ratio, fitting Planck data.
- Resonance effects have minimal impact on non-Gaussianity.

## Abstract

We consider single field chaotic inflationary models plus a cosine modulation term, as in axion monodromy models, and augment it by a light scalar field with similar cosine coupling. We show the power spectrum of curvature perturbations of this model is dominated by the one-loop contribution to inflaton two-point function which is enhanced due to resonant interactions. This allows to disentangle the scale of scalar and tensor perturbations and hence to suppress the ratio of tensor-to-scalar power spectra and alters the expression of scalar spectral tilt from the simple chaotic models, thus opening the way to reconcile chaotic models with convex potential and the Planck data. As in monodromy inflation models, we also have a cosine modulation in spectral tilt. We mention that contribution of resonance effects on non-Gaussianty is small and it remains within the current bounds. Resonant production of light particles toward the end of inflation may set the stage for a successful reheating model.