Postinflationary scalar tensor cosmology and inflationary parameters

Abstract

Scalar fields provide attractive modifications of pre-BBN cosmology, which have interesting implications for dark matter abundances. We analyze the effect of these modifications on the number of e-foldings between the horizon exit of cosmic microwave background modes and the end of inflation (Nk), and examine the consequences for inflationary predictions of various models. We find significant effects in the predictions in the (ns,r) plane. For a large part of the parameter space, the shift in Nk is positive; this ameliorates the tension of m2φ2 and natural inflation with data.