Plateau Inflation from Random Non-Minimal Coupling

TL;DR

This paper demonstrates that a generic non-minimal coupling can naturally produce plateau inflation consistent with observations, with the coupling strength determining the inflationary regime and predictions.

Contribution

It provides analytic and numerical evidence that non-minimal coupling naturally leads to viable plateau inflation, explaining observed inflationary parameters without fine-tuning.

Findings

Non-minimal coupling pushes higher-order potential terms out of the inflationary regime.

For coupling strength around $N_e^2$, the field remains sub-Planckian during inflation.

Large coupling values lead to predictions matching PLANCK data, including $\xi \,\simeq 10^4$.

Abstract

A generic non-minimal coupling can push any higher-order terms of the scalar potential sufficiently far out in field space to yield observationally viable plateau inflation. We provide analytic and numerical evidence that this generically happens for a non-minimal coupling strength $\xi$ of the order $N_e^2$. In this regime, the non-minimally coupled field is sub-Planckian during inflation and is thus protected from most higher-order terms. For larger values of $\xi$, the inflationary predictions converge towards the sweet spot of PLANCK. The latter includes $\xi\simeq 10^4$ obtained from CMB normalization arguments, thus providing a natural explanation for the inflationary observables measured.