Primordial blackholes and gravitational waves for an inflection-point model of inflation

In this article we provide a new closed relationship between cosmic abundance of primordial gravitational waves and primordial blackholes that originated from initial inflationary perturbations for inflection-point models of inflation where inflation occurs below the Planck scale. The current Planck constraint on tensor-to-scalar ratio, running of the spectral tilt, and from the abundance of dark matter content in the universe, we can deduce a strict bound on the current abundance of primordial blackholes to be within a range, 9.99712 x 10(-3) < Omega(PBH)h(2) < 9.99736 x 10(-3). (C) 2014 The Authors. Published by Elsevier B.V.