Constraints on primordial density perturbations from induced gravitational waves

Abstract

We consider the stochastic background of gravitational waves produced during the radiation-dominated hot big bang as a constraint on the primordial density perturbation on comoving length scales much smaller than those directly probed by the cosmic microwave background or large-scale structure. We place weak upper bounds on the primordial density perturbation from current data. Future detectors such as BBO and DECIGO will place much stronger constraints on the primordial density perturbation on small scales. DOI: http://dx.doi.org/10.1103/PhysRevD.81.023527 Received 24 July 2009Revised 17 December 2009Published 22 January 2010© 2010 The American Physical Society