  Vacuum fluctuations in the inflaton field driving chaotic inflation with a
quadratic potential give a red spectrum of primordial density perturbations,
n=0.97. However angular fluctuations in an O(N)-symmetric quadratic potential
have a very nearly scale-invariant spectrum, n=0.9998. We investigate the
possibility that these isocurvature field perturbations could give the dominant
contribution to the primordial density perturbation after inflation.
