Bogoliubov Excited States and the Lyth Bound
  We show that Bogoliubov excited scalar and tensor modes do not alleviate
Planckian evolution during inflation if one assumes that $r$ and the Bogoliubov
coefficients are approximately scale invariant. We constrain the excitation
parameter for the scalar fluctuations, $\beta$, and tensor perturbations,
$\tilde{\beta}$, by requiring that there be at least three decades of scale
invariance in the scalar and tensor power spectrum. For the scalar fluctuations
this is motivated by the observed nearly scale invariant scalar power spectrum.
For the tensor fluctuations this assumption may be shown to be valid or invalid
by future experiments.
