In cosmic inflation driven by a scalar gauge singlet field with a tree level Higgs potential, the scalar to tensor ratio $r$ is estimated to be larger than 0.036, provided the scalar spectral index $n_s\ge 0.96$. We discuss quantum smearing of these predictions arising from the inflaton couplings to other particles such as grand unified theory scalars, and show that these corrections can significantly decrease $r$. However, for $n_s\ge 0.96$, we obtain $r\ge 0.02$ which can be tested by the Planck satellite.

• Received 4 April 2010

DOI:https://doi.org/10.1103/PhysRevD.81.123525