Exploring the Spectral Shape of Gravitational Waves Induced by Primordial Scalar Perturbations and Connection with the Primordial Black Hole Scenarios

Understand

There is a growing expectation that the gravitational wave detectors will start probing the stochastic gravitational wave backgrounds in the following years.

• We explore the spectral shapes of gravitational waves induced to second order by scalar perturbations and presumably have been produced in the early universe.
• We calculate the gravitational wave spectra generated during radiation and kination eras together with the associated primordial black hole counterpart.
• We employ power spectra for the primordial curvature perturbation generated by $\alpha$-attractors and nonminimal derivative coupling inflation models as well as Gaussian and delta-type shapes.