Dynamical Inflection Point Inflation

TL;DR

This paper introduces a universal inflaton potential with multiple inflection points derived from the Coleman-Weinberg mechanism, compatible with small-field inflation and testable by future CMB experiments.

Contribution

It proposes a novel mechanism for multiple inflection points in the inflaton potential based on gauge coupling beta function zeros, applicable across various models.

Findings

Predicts small tensor-to-scalar ratio.

Identifies branches with positive and negative spectral index running.

Positive running branch testable by upcoming CMB experiments.

Abstract

We provide a mechanism to obtain multiple inflection points for the inflaton potential based on the Coleman-Weinberg potential. The key ingredient is the existence of zeros of the inflaton quartic coupling beta function, which can be simply realized by a sign change of a gauge coupling beta function at a massive threshold scale in gauge-Yukawa models. A universal inflaton potential emerges for a wide range of models and can accommodate the experimental data in the small-field inflation scenario. While the ratio of tensor over scalar amplitudes is predicted to be small, the running of the scalar spectral index, $\alpha_s$, has branches with both positive and negative values. The positive branch with $\alpha_s \gtrsim 0.002$ will be tested by the coming cosmic microwave background experiments.