We report on new structures uncovered in the study of cosmological correlators. While these objects have historically been used to study observables in de Sitter space, they share properties with analogous objects in flat space and are therefore relevant in a broader context. Traditionally, such correlators are also known as in-in correlators, as they are computed using the in-in (Schwinger-Keldysh) formalism. However, since the advent of AdS/CFT, such observables have also been computed using other formalisms, such as the wavefunction of the universe (where they are viewed as CFT correlators). In this talk, I will give a pedagogical introduction to these correlators and walk through recent progress made in studying them at both tree and loop levels. In particular, I will emphasize the simplicity of the "final answers" compared to the "individual building blocks", a feature often contrasted with scattering amplitudes.

Biography

Chandramouli Chowdhury works on cosmological correlators, with a particular interest in their connections to scattering amplitudes and asymptotic symmetries. He completed his PhD under the supervision of Suvrat Raju and is currently a postdoctoral researcher at the University of Southampton. He will soon join the Institute of Theoretical Physics, Chinese Academy of Sciences (ITP-CAS). 

Inviter: Song He