Quantum Gravity in the Sky: Interplay between fundamental theory and
  observations
  Observational missions have provided us with a reliable model of the
evolution of the universe starting from the last scattering surface all the way
to future infinity. Furthermore given a specific model of inflation, using
quantum field theory on curved space-times this history can be pushed
\emph{back in time} to the epoch when space-time curvature was some $10^{62}$
times that at the horizon of a solar mass black hole! However, to extend the
history further back to the Planck regime requires input from quantum gravity.
An important aspect of this input is the choice of the background quantum
geometry and of the Heisenberg state of cosmological perturbations thereon,
motivated by Planck scale physics. This paper introduces first steps in that
direction. Specifically we propose two principles that link quantum geometry
and Heisenberg uncertainties in the Planck epoch with late time physics and
explore in detail the observational consequences of the initial conditions they
select. We find that the predicted temperature-temperature (T-T) correlations
for scalar modes are indistinguishable from standard inflation at small angular
scales even though the initial conditions are now set in the deep Planck
regime. However, \emph{there is a specific power suppression at large angular
scales}. As a result, the predicted spectrum provides a better fit to the
PLANCK mission data than standard inflation, where the initial conditions are
set in the general relativity regime. Thus, our proposal brings out a deep
interplay between the ultraviolet and the infrared. Finally, the proposal also
leads to specific predictions for power suppression at large angular scales
also for the (T-E and E-E) correlations involving electric polarization. The
PLANCK team is expected to release this data in the coming year.
