Resolving primordial physics through correlated signatures

Understand

We discuss correlations among spectral observables as a new tool for differentiating between models for the primordial perturbation.

• We show that if generated in the isocurvature sector, a running of the scalar spectral index is correlated with the statistical properties of non-Gaussianities.
• In particular, we find a large running will inevitably be accompanied by a large running of $f_{\rm NL}$ and enhanced $g_{\rm NL}$, with $g_{\rm NL}\gg f_{\rm NL}^2$.
• If the tensor to scalar ratio is large, a large negative running must turn positive on smaller scales.