Intermediate inflation under the scrutiny of recent data
  We use the flow equations to determine the different hierarchy Hubble parameters as a function of the number of e-folds for intermediate models in single-field inflation. The obtained expressions allow us to determine at second order in the hierarchy Hubble parameters different observational parameters. We distinguish the scalar spectral index, its running and the tensor-to-scalar ratio, among others. Recently, it has been noticed that measurements released by Planck, combined with the WMAP large-angle polarization are in tension with this sort of model. Here, we show in detail why this occur. The conclusions do not change even when the recent BICEP2 data are included. 
Sergio del Campo
astro-ph.CO gr-qc hep-th