Stimulated creation of quanta during inflation and the observable
  universe
  Inflation provides a natural mechanism to account for the origin of cosmic
structures. The generation of primordial inhomogeneities during inflation can
be understood via the spontaneous creation of quanta from the vacuum. We show
that when the corresponding {\it stimulated} creation of quanta is considered,
the characteristics of the state of the universe at the onset of inflation are
not diluted by the inflationary expansion and can be imprinted in the spectrum
of primordial inhomogeneities. The non-gaussianities (particularly in the
so-called squeezed configuration) in the cosmic microwave background and galaxy
distribution can then tell us about the state of the universe that existed at
the time when quantum field theory in curved spacetime first emerged as a
plausible effective theory.
