Production of gravitational waves during preheating with nonminimal coupling

TL;DR

This paper investigates how nonminimal coupling during preheating after inflation amplifies gravitational wave production, potentially making these signals detectable and providing insights into early universe physics.

Contribution

It demonstrates that nonminimal coupling enhances gravitational wave signals during preheating, offering a new observational window into inflationary physics.

Findings

Enhanced amplitude of gravitational wave spectrum due to nonminimal coupling

Distinctive peaks in GW spectrum reveal properties of nonminimal coupling

Potential detectability of GW signals in future experiments

Abstract

We study the preheating and the in-process production of gravitational waves (GWs) after inflation in which the inflaton is nonminimally coupled to the curvature in a self-interacting quartic potential with the method of lattice simulation. We find that the nonminimal coupling enhances the amplitude of the density spectrum of inflaton quanta, and as a result, the peak value of the GW spectrum generated during preheating is enhanced as well and can reach the limit of detection in future GW experiments. The peaks of the GW spectrum not only exhibit distinctive characteristics as compared to those of minimally coupled inflaton potentials but also imprint information on the nonminimal coupling and the parametric resonance, and thus the detection of these peaks in the future will provide us a new avenue to reveal the physics of the early universe.