Loop inflection-point inflation

Abstract

A novel inflection-point inflation model is analysed. The model considers a massless scalar field, whose self-coupling's running is stabilised by a non-renormalisable operator. The running is controlled by a fermion loop. We find that successful inflation is possible for a natural value of the Yukawa coupling $y\simeq 4\times 10^{-4}$. The necessary fine-tuning is only $\sim 10^{-6}$, which improves on the typical tuning of inflection-point inflation models, such as MSSM inflation. The model predicts a spectral index within the 1-$\sigma$ bound of the latest CMB observations, with negligible tensors ($r\sim 10^{-(9-10)}$). These results are largely independent of the order of the stabilising non-renormalisable operator.