Abstract
We study gravitational waves (GWs) induced by non-Gaussian curvature perturbations. We calculate the density parameter per logarithmic frequency interval, , given that the power spectrum of the curvature perturbation has a narrow peak at some small scale , with a local-type non-Gaussianity, and constrain the nonlinear parameter with the future LISA sensitivity curve as well as with constraints from the abundance of the primordial black holes (PBHs). We find that the non-Gaussian contribution to increases as , peaks at , and has a sharp cutoff at . The non-Gaussian part can exceed the Gaussian part if . If both a slope with and the multiple-peak structure around a cutoff are observed, it can be recognized as a smoking gun of the primordial non-Gaussianity. We also find that if PBHs with masses of to are identified as cold dark matter of the Universe, the corresponding GWs must be detectable by LISA-like detectors, irrespective of the value of or .
- Received 22 November 2018
- Revised 6 March 2019
DOI:https://doi.org/10.1103/PhysRevLett.122.201101
© 2019 American Physical Society