Speaker
Arthur Lipstein
(University of Durham)
Description
The basic observables in cosmology are known as in-in correlators. Recent calculations have revealed that in-in correlators in de Sitter space exhibit hidden simplicity stemming from a close relation to scattering amplitudes in flat space. In this talk, I will explain how to make this property manifest by dressing flat space Feynman diagrams with certain auxiliary propagators. Such dressing rules can be derived for a broad range of scalar theories, including those with IR divergences. If time permits, I will sketch how to extend this to spinning fields and formulate the double copy for in-in correlators.
