Entropy production in inflation from spectator loops
  Perturbations in cosmic microwave background (CMB) photons and large scale
structure of the universe are sourced primarily by the curvature perturbation
which is widely believed to be produced during inflation. In this paper we
present a 2-field inflationary model in which the inflaton couples
bi-quadratically to a spectator field. We show that the spectator induces a
rapid growth of the momentum of the curvature perturbation and the associated
Gaussian van Neumann entropy during inflation such that the initial conditions
at the end of inflation are substantially different from the standard ones.
Consequently, one ought to reconsider the kinetic equations describing
evolution of the photon, dark matter and baryonic fluids in radiation and
matter eras and take account of the fact that the curvature perturbation and
its canonical momentum are two {\it a priory} independent stochastic fields. We
also briefly analyze possible imprints on the CMB temperature fluctuations from
the more general inflationary scenario which contains light spectator fields
coupled to the inflaton.
