New Method to Probe Primordial Non-Gaussianities via Gravitational Waves

Recent research has introduced a new method for probing primordial non-Gaussianities (NGs) through the observation of gravitational waves (GWs) induced by primordial black holes (PBHs). The study, titled "New probe of non-Gaussianities with primordial black hole induced gravitational waves," was authored by Theodoros Papanikolaou, Xin-Chen He, Xiao-Han Ma, Yi-Fu Cai, Emmanuel N. Saridakis, and Misao Sasaki.

The researchers propose that the existence of primordial NGs can leave distinct imprints on the clustering properties of PBHs and the spectral shape of the GWs they induce. Specifically, they focus on a scale-dependent local-type NG and identify a unique double-peaked GW energy spectrum. This spectrum may fall within the frequency bands of upcoming gravitational wave observatories, such as LISA, Einstein Telescope (ET), Square Kilometre Array (SKA), and Big Bang Observer (BBO).

The findings suggest that these gravitational wave signals could serve as a novel method for probing primordial NGs. The study also establishes a joint limit on the effective non-linearity parameter for the primordial tri-spectrum and the primordial curvature perturbation power spectrum, which could have implications for future observational strategies in cosmology.

This research was accepted in Physics Letters B and is available for further reading on arXiv under the identifier arXiv:2403.00660.