UV-protected (Natural) Inflation: Primordial Fluctuations and
  non-Gaussian Features
  We consider the UV-protected inflation, where the inflaton potential is
obtained by quantum (one-loop) breaking of a global symmetry into a discrete
symmetry. In this model, all coupling scales are sub-Planckian. This is
achieved by coupling the inflaton kinetic term to the Einstein tensor such that
the friction is enhanced gravitationally at high energies. In this respect,
this new interaction makes virtually any potential adequate for inflation while
keeping the system perturbative unitary. We show that even if the
gravitationally enhanced friction intrinsically contains new nonlinearities,
the UV-protected inflation (and any similar models) behaves as a single field
scenario with red tilted spectrum and potentially detectable gravitational
waves. Interestingly enough, we find that non-Gaussianity of the curvature
perturbations in the local form are completely dominated by the nonlinear gauge
transformation from the spatially flat to uniform-field gauge and/or by parity
violating interactions of the inflaton and gauge bosons. In particular, the
parity violating interactions may produce detectable non-Gaussianity.
