A Note on Calm Excited States of Inflation
  We identify a two-parameter family of excited states within slow-roll
inflation for which either the corrections to the two-point function or the
characteristic signatures of excited states in the three-point function -- i.e.
the enhancement for the flattened momenta configurations-- are absent. These
excited states may nonetheless violate the adiabaticity condition maximally. We
dub these initial states of inflation calm excited states. We show that these
two sets do not intersect, i.e., those that leave the power-spectrum invariant
can be distinguished from their bispectra, and vice versa. The same set of calm
excited states that leave the two-point function invariant for slow-roll
inflation, do the same task for DBI inflation. However, at the level of
three-point function, the calm excited states whose flattened configuration
signature is absent for slow-roll inflation, will lead to an enhancement for
DBI inflation generally, although the signature is smaller than what suggested
by earlier analysis. This example also illustrates that imposing the Wronskian
condition is important for obtaining a correct estimate of the non-Gaussian
signatures.
