Monodromy inflation at strong coupling: $4\pi$ in the sky

TL;DR

This paper develops a simple effective field theory for monodromy inflation at strong coupling, showing it can produce stable, prolonged inflation with suppressed tensor modes and potentially observable non-Gaussianity.

Contribution

It introduces a new class of flux monodromy models incorporating strong coupling effects that flatten the potential and activate higher derivative operators, enhancing inflationary model versatility.

Findings

Models are stable against radiative and non-perturbative corrections.

Can sustain over 60 e-folds of inflation.

Predicts low tensor-to-scalar ratio and potentially observable non-Gaussianity.

Abstract

We present a simple effective field theory formulation of a general family of single field flux monodromy models for which strong coupling effects at large field values can flatten the potential and activate operators with higher powers of derivatives. These models are radiatively and non-perturbatively stable and can easily sustain $\ga 60$ efolds of inflation. The dynamics combines features of both large field chaotic inflation and $k$-inflation, both of which can suppress the tensor amplitude. Reducing the tensor-scalar ratio below the observational bound $r \lesssim 0.1$ while keeping the scalar spectral index $n_s$ within experimental bounds either yields equilateral nongaussianity $f_{NL}^{eq} \simeq {\cal O}(1)$, close to the current observational bounds, or ultimately gives very small $r$.