Limits on Semiclassical Fluctuations in the Primordial Universe
  We place limits on semiclassical fluctuations that might be present in the
primordial perturbation spectrum. These can arise if some signatures of
pre-inflationary features survive the expansion, or could be created by
whatever mechanism ends inflation. We study two possible models for such
remnant fluctuations, both of which break the isotropy of CMB on large scales.
We first consider a semiclassical fluctuation in one Fourier mode of primordial
perturbations. The second scenario we analyze is a semiclassical Gaussian bump
somewhere in space. These models are tested with the seven-year WMAP data using
a Markov Chain Monte Carlo Bayesian analysis, and we place limits on these
fluctuations. The upper bound for the amplitude of a fluctuation in a single
Fourier mode is a<=10^(-4), while for the Gaussian bump a<=10^(-3).
