Unitarity, Recursion and Soft Limits in (EA)dS through Dressing

Abstract

Using the recently developed framework in which cosmological correlators in (E)AdS are represented as flat-space amplitudes dressed by auxiliary propagators, we show that several structural properties of the cosmological observables have a direct flat-space origin. We derive cosmological cutting rules for spinning correlators from the flat-space optical theorem, obtain the cosmological tree theorem from the Feynman tree theorem, and uplift BCFW recursion relations to (E)AdS via dressing. We also show that flat-space soft theorems reproduce the soft limits of (E)AdS correlators, and find indications of an emergent universal structure in subleading soft limits. These results provide evidence that key features of cosmological correlators can be systematically understood as dressed manifestations of flat-space physics.