Multi-Natural Inflation
  We propose a multi-natural inflation model in which the single-field inflaton
potential consists of two or more sinusoidal potentials that are comparable in
size, but have different periodicity with a possible non-zero relative phase.
The model is versatile enough to realize both large-field and small-field
inflation. We show that, in a model with two sinusoidal potentials, the
predicted values of the spectral index and tensor-to-scalar ratio lie within
the $1\sigma$ region of the Planck data. In particular, there is no lower bound
on the decay constants in contrast to the original natural inflation. We also
show that, in a certain limit, multi-natural inflation can be approximated by a
hilltop quartic inflation model.
