Speaker
Guanhao Sun
(Chongqing University)
Description
Equal-time in-in correlation functions are important observables for cosmological models and quantum field theories. In this talk, I will first explore how the Wilsonian renormalization group and effective field theory (EFT) apply to these observables in both flat and de Sitter space. Specifically, matching the UV and IR requires additional terms not captured by conventional EFT. These terms are collected in the influence functional from a Schwinger-Keldysh path integral point of view and are related to the evolution of the density matrix. Explicit examples show how matching is done in flat spacetime, and that in de Sitter spacetime these terms can become exponentially suppressed.
Author
Guanhao Sun
(Chongqing University)