More on pre-inflationary non Gaussianities

Abstract

Abstract I generalize the three-point amplitude of curvature perturbations in the climbing scenario inspired by ten-dimensional non-supersymmetric strings to a broader class of exponential potentials, under some assumptions on the smoothing effects of String Theory that favor a bounce Cosmology. The extension can encompass the $$SO(16)\times SO(16)$$ S O ( 16 ) × S O ( 16 ) model, together with other scenarios related to supersymmetry breaking in String Theory. Above and beyond this scheme, the turning point leaves an exactly calculable imprint on the correlators, which is determined by a residue and points to a narrow e -fold range centered around $$N \simeq 63$$ N ≃ 63 . The e -fold ranges compatible with Planck data move toward lower values of N for milder potentials and toward larger values for steeper ones. I also compute the three-point amplitudes involving graviton modes in the same bounce scenario, showing in detail their lack of peculiar contributions from the turning point.