Rescattering of non-minimal coupling scalar particles during inflation

TL;DR

This paper studies how non-minimally coupled scalar particles produced during inflation can rescatter off the inflaton, significantly affecting the primordial power spectrum and generating notable non-Gaussianities.

Contribution

It introduces a detailed analysis of rescattering effects from non-minimally coupled scalars during inflation, highlighting their impact on primordial perturbations and non-Gaussianity.

Findings

Resonant particle production is greatly enhanced by non-minimal coupling.

Rescattering leads to large amplitude features in the power spectrum at specific scales.

Significant non-Gaussianities are generated through this mechanism.

Abstract

We investigate the rescattering effects arising from non-minimally coupled scalar particles $\chi$ that are suddenly produced during inflation. The coupling term $\xi R \chi^2$ significantly enhances resonant particle production compared to minimal coupling scenarios. Consequently, the produced $\chi$ particles rescattering off the homogeneous inflaton condensate $\phi$, generating abundant $\delta\phi$ quanta within very short time intervals. This process leads to characteristic enhancements in the power spectrum of primordial curvature perturbations at scales corresponding to the moments of particle production. When this occurs at small scales, the power spectrum amplitude can reach as high as $\mathcal{O}(10^{-2})$. Furthermore, analysis of the equilateral bispectrum shows that this mechanism also induces substantial non-Gaussian features.