24.11.2021 (Wednesday)

Conformal bootstrap meets cosmology

Regular Seminar Matthijs Hogervorst (EPFL)

13:45 KCL
room K0.20

Local observables in a de Sitter universe become conformal, if you wait long enough. Indeed, one can study the imprints of inflation by looking at conformal correlations in the sky. There’s an ongoing effort in the cosmology community to understand these late-time correlators from first principles, without invoking a specific Lagrangian. In this talk, I will discuss the late-time CFT living in de Sitter through the lens of a quantum field theorist. The CFT in question shares many features with its counterparts in flat space or AdS, but differs in crucial aspects: in particular, it can have complex scaling dimensions and correlation functions. I will nevertheless argue that de Sitter CFTs have good unitarity properties and can be constrained via conformal bootstrap equations. This observation should open up a new way to constrain cosmological correlation functions.