On-shell Factorization of Inflation Correlators at All Loop Orders

Abstract

Inflation correlators are boundary correlation functions of quantum fields living in the bulk dS. They are important data for QFT in dS and are promising observables of cosmological collider physics. In this talk, the speaker will present their recent and ongoing works in understanding the analytical structure of inflation correlators with massive exchanges at all loop orders. He will introduce a particular type of nonanalyticity, called a nonlocal signal, and explain why it is phenomenologically important. Then, with the techniques of partial Mellin-Barnes representation, he will present a signal-detection algorithm that helps us to identify all nonlocal signals in a given soft limit. He will also introduce a factorization theorem for the nonlocal signal, very similar to the on-shell factorization of scattering amplitudes in the flat space. Finally, if time permits, he will describe an intuitive way to understand the factorization theorem from a boundary OPE viewpoint.

About the Speaker

Prof. XIANYU Zhong-Zhi is an Associate Professor at the Department of Physics at Tsinghua University. He obtained his PhD in 2015 from the same University then became a postdoc at Harvard University from 2015 to 2020. He works in theoretical particle physics and cosmology. His recent research interests include cosmological collider physics, quantum field theory and amplitude techniques in curved spacetime, new physics in the early universe and in astrophysical systems, gravitational wave astronomy, etc.

About the Program

For more information, please refer to the program website at http://iasprogram.ust.hk/particle_theory.

For Attendees' Attention

• Seating is on a first come, first served basis.