On graviton non-Gaussianities in the Effective Field Theory of Inflation

A bstract We derive parity-even graviton bispectra in the Effective Field Theory of Inflation (EFToI) to all orders derivatives. Working perturbation theory, we construct cubic interactions that can contribute tree-level bispectra, showing they come from EFToI operators containing two or three powers extrinsic curvature and its covariant derivatives: other be removed by field redefinitions start at higher-order perturbations. For curvature, where single-clock consistency relations are satisfied without a correction two-point function, use Manifestly Local Test (MLT) efficiently extract effects evolving fluctuations end inflation. Despite somewhat complicated nature bulk interactions, final boundary correlators take very compact form. quadratic leading order sum contact single exchange diagrams, which tied together spatial diffeomorphisms, derivatives these computing necessary time integrals. diagrams exploit factorisation properties bulk-bulk propagator for massless gravitons write result as finite over residues. Perhaps surprisingly, show contributions have only total-energy poles also satisfy MLT.