Two-Field Analysis of No-Scale Supergravity Inflation
  Since the building-blocks of supersymmetric models include chiral superfields
containing pairs of effective scalar fields, a two-field approach is
particularly appropriate for models of inflation based on supergravity. In this
paper, we generalize the two-field analysis of the inflationary power spectrum
to supergravity models with arbitrary K\"ahler potential. We show how two-field
effects in the context of no-scale supergravity can alter the model predictions
for the scalar spectral index $n_s$ and the tensor-to-scalar ratio $r$,
yielding results that interpolate between the Planck-friendly Starobinsky model
and BICEP2-friendly predictions. In particular, we show that two-field effects
in a chaotic no-scale inflation model with a quadratic potential are capable of
reducing $r$ to very small values $\ll 0.1$. We also calculate the
non-Gaussianity measure $f_{\rm NL}$, finding that is well below the current
experimental sensitivity.
