Non-Gaussianity and the induced gravitational wave background

TL;DR

This paper investigates how primordial non-Gaussianity influences the spectrum of gravitational waves induced by scalar fluctuations, highlighting the importance of trispectrum components and providing numerical results for various curvature spectra.

Contribution

It offers a detailed numerical analysis of the effects of primordial non-Gaussianity, including trispectrum contributions, on the induced gravitational wave background.

Findings

Primordial non-Gaussianity significantly affects the gravitational wave spectrum.

Connected and disconnected trispectrum components both contribute to the signal.

Results vary with different primordial curvature power spectra.

Abstract

Scalar metric fluctuations generically source a spectrum of gravitational waves at second order in perturbation theory, poising gravitational wave experiments as potentially powerful probes of the small-scale curvature power spectrum. We perform a detailed study of the imprint of primordial non-Gaussianity on these induced gravitational waves, emphasizing the role of both the disconnected and connected components of the primoridal trispectrum. Specializing to local-type non-Gaussianity, we numerically compute all contributions and present results for a variety of enhanced primordial curvature power spectra.