Speaker
Description
Soft de Sitter Effective Theory (SdSET) is a promising candidate for the correct effective description of superhorizon modes of quantum fields in de Sitter spacetime. It is especially valuable for achieving control over theories with strong infrared effects. A prototypical example is the massless, minimally coupled scalar field, whose correlation functions are infrared-divergent in perturbation theory. However, the interacting theory self-regularizes these divergences non-perturbatively by dynamically generating a mass scale, a phenomenon that was first understood within the formalism of stochastic inflation. In the SdSET this formalism emerges as a consequence of operator mixing under renormalization, and the EFT offers the possibility to systematically include higher-order corrections to the Fokker-Planck equation. In this talk, I will introduce the SdSET, show how to renormalize and match composite operators in dimensional regularization to their full-theory counterparts, and demonstrate how the EFT can be used to compute the first quantum correction to the diffusion term.