Testing quantum gravity effects with latest CMB observations
  Inspired by quantum gravitational physics, the approach of non-commutative
(NC) phase space leads to a modified dispersion relation of gravitational
waves. This feature, if applied to the very early universe, gives rise to a
modified power spectrum of primordial tensor perturbations with a suppression
of power on large scales. We confront this phenomenon with the BICEP2 and
Planck experiments, and show that inflation with the modified dispersion
relation can simultaneously fit the observations better than the standard
inflationary paradigm. In particular, the numerical result implies that with
the latest cosmological microwave background (CMB) observations, a quantum
gravity modified power spectrum of primordial tensor modes is preferred at a
statistical significance of more than $3\sigma$ compared with the minimal
model. Our study indicates that the potential tension between the BICEP2 and
Planck data may be resolved by quantum gravity effects.
