Non-Gaussianity in Loop Quantum Cosmology
  We extend the phenomenology of loop quantum cosmology (LQC) to second order
in perturbations. Our motivation is twofold. On the one hand, since LQC
predicts a cosmic bounce that takes place at the Planck scale, the second order
contributions could be large enough to jeopardize the validity of the
perturbative expansion on which previous results rest. On the other hand, the
upper bounds on primordial non-Gaussianity obtained by the Planck Collaboration
are expected to play a significant role on explorations of the LQC
phenomenology. We find that the bounce in LQC produces an enhancement of
non-Gaussianity of several orders of magnitude, on length scales that were
larger than the curvature radius at the bounce. Nonetheless, we find that one
can still rely on the perturbative expansion to make predictions about
primordial perturbations. We discuss the consequences of our results for LQC
and its predictions for the cosmic microwave background.
