IAS Fundamental Physics Seminar Series - A Match Made in Heaven: Linking Observables in Inflationary Cosmology

Abstract
The non-Gaussian statistics of primordial perturbations is a pristine tracer of new physics in the early universe. Traditionally, different correlators are computed independently using diagrammatics given the underlying Lagrangian. However, such computations work diagram-by-diagram and are often obscured by heavy mathematics. In this talk, the speaker will show that different correlator observables are, in fact, not independent. Rather, there exist subterranean connections among correlators that bypass the technical complexities. Starting from generic assumptions, he will establish a reality theorem which then translates to an infinite family of cutting rules linking higher-point correlators to lower-point ones. As a concrete application, he will show that the parity-odd curvature trispectrum is a precise “double copy” of the curvature-graviton mixed bispectrum whenever a gravitational Chern-Simons term is involved. Such relations are the first cosmological cutting rules that can be observationally tested and serve as a smoking gun towards physics in the primordial universe.