Loop corrections to primordial non-Gaussianity

We discuss quantum gravitational loop effects to observable quantities such as curvature power spectrum and primordial non-Gaussianity of cosmic microwave background (CMB) radiation. We first review the previously shown case where one gets a time dependence for zeta-zeta correlator due to loop corrections. Then we investigate the effect of loop corrections to primordial non-Gaussianity of CMB. We conclude that, even with a single scalar inflaton, one might get a huge value for non-Gaussianity which would exceed the observed value by at least 30 orders of magnitude. Finally we discuss the consequences of this result for scalar driven inflationary models.

Figure 1

One-loop correction is sourced by cubic and quartic self-interactions of $\zeta$.

Figure 2

Bispectrum: Tree level and corrections to external legs.

Figure 3

The remaining diagram at one-loop order.