Robustness of Inflation to Large Tensor Perturbations
  Extending our previous work on the robustness of inflation to perturbations
in the scalar field, we investigate the effects of perturbations in the
transverse traceless part of the extrinsic curvature on the evolution of an
inhomogeneous inflaton field. Focusing on small field models, we show that
these additional metric inhomogeneities initially reduce the total number of
e-folds as the amplitude increases, but that the reduction saturates and even
reverses above a certain amplitude. We present an argument that this is due to
the presence of a large initial Hubble friction when metric perturbations are
large.
