Universality in Multifield Inflation from String Theory
  We develop a numerical statistical method to study linear cosmological
fluctuations in inflationary scenarios with multiple fields, and apply it to an
ensemble of six-field inflection point models in string theory. The latter are
concrete microphysical realizations of quasi-single-field inflation, in which
scalar masses are of order the Hubble parameter and an adiabatic limit is
reached before the end of inflation. We find that slow-roll violations, bending
trajectories and 'many-field' effects are commonplace in realizations yielding
more than 60 e-folds of inflation, although models in which these effects are
substantial are in tension with observational constraints on the tilt of the
scalar power spectrum.
