Diagrammatic approach to non-Gaussianity from inflation

We present Feynman type diagrams for calculating the n-point function of theprimordial curvature perturbation in terms of scalar field perturbations duringinflation. The diagrams can be used to evaluate the corresponding terms in then-point function at tree level or any required loop level. Rules are presentedfor drawing the diagrams and writing down the corresponding terms in real spaceand Fourier space. We show that vertices can be renormalised to automaticallyaccount for diagrams with dressed vertices. We apply these rules to calculatethe primordial power spectrum up to two loops, the bispectrum including loopcorrections, and the trispectrum.