Speaker: Godfrey Leung

Abstract:

We explore the correlations between primordial non-Gaussianity and isocurvature perturbation in the early universe by studying a concrete model of a Peccei-Quinn type field with generic gravitational couplings. We illustrate explicitly how the primordial bispectrum correlates with the cross-correlation power spectrum. Assuming the resulting $\fnl \sim \calO(1)$, we find that the form of the correlation depends mostly upon the inflation model but only weakly on the axion parameters, even though $\fnl$ itself does depend heavily on the axion parameters.