Dynamical Inflection Point Inflation

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.

Comments: 22 pages, 7 figures. v2: New section discussing attractor solutions, new plot with ns vs r, version accepted in JCAP