Large tensor-to-scalar ratio and low scale inflation
arXiv:0712.2031
Abstract
It is plausible that the scalar density perturbations are created by a relatively low scale model of inflation which predicts the CMB anisotropy and excites Standard Model baryon and cold dark matter, but negligible gravity waves. Nevertheless a significantly large tensor perturbations can be observed if there exists a prior phase of high scale inflation separated by a matter or radiation dominated epoch. In this paper we provide a simple example when the gravity waves generated at high scales trickle through the horizon of the second phase of inflation and leave a distinct imprint in the spectrum of the tensor modes. For a high scale inflation occurring at GeV while the second phase of inflation happening at GeV, the largest tensor to scalar ratio is bounded by .
9 pages+8 figures; v2: small changes, added discussion, new figures