Whipped inflation
  Motivated by the idea that inflation occurs at the GUT symmetry breaking
scale, in this paper we construct a new class of large field inflaton
potentials where the inflaton starts with a power law potential; after initial
period of relative fast roll that lasts until after a few e-folds inside the
horizon, it transits to the attractor of the slow roll part of the potential
with a lower power. Due to the initial fast roll stages of inflation, we find a
suppression in scalar primordial power at large scales and at the same time the
choice of the potential can provide us a tensor primordial spectrum with high
amplitude. This suppression in scalar power with a large tensor-to-scalar ratio
helps us to reconcile the Planck and BICEP2 data in a single framework. We find
that a transition from a cubic to quadratic form of inflaton potential
generates an appropriate suppression in power of scalar primordial spectrum
that provides significant improvement in fit compared to power law model when
compared with Planck and BICEP2 data together. We calculate the extent of
non-Gaussianity, specifically, the bispectrum for the best fit potential and
show that it is consistent with Planck bispectrum constraints.
