Abstract

The on-shell approach to computing scattering amplitudes has produced tremendous progress in particle physics. The combination of symmetries, locality and unitarity allows one to efficiently explore the space of consistent effective theories of massless particles without using Lagrangians or introducing gauge redundancies. Effort has recently turned to applying a similar logic to “bootstrap” the fundamental observables in cosmology, namely cosmological correlators that live on the late-time boundary of an approximately de-Sitter spacetime. After outlining the success of the on-shell approach for particle physics, I will explain how we can efficiently bootstrap three and four point functions in the effective field theory of inflation by using a small number of physical principles. I will also show how this new approach to computing cosmological observables allows us to make some very general statements about parity-violating gravitational interactions on inflationary backgrounds.