Title: Differential equations and recursive solutions for cosmological amplitudes

Speaker: Xuhang Jiang (Institute of Theoretical Physics, Chinese Academy of Sciences)

Time: 1:30 pm, Sept 19 (Thursday) 2024

Venue: Physics Building W105

Abstract: The study of “cosmological amplitudes”, i.e. cosmological wavefunctions and correlation functions, provides us invaluable information about the primordial universe and quantum field theory in curved spacetime. Recently, an interesting toy model, conformal scalar field theory with non-conformal self-interactions in FRW universe, has been studied a lot using different frameworks. In this work, we combine the differential equations (DEs) method with family-tree decomposition and obtaine Euler integral representations for the family-tree integrals which have a recursive structure. In this way, we reproduce the series expansion results given in the literature and study the de-Sitter limit under this representation. The differential equations of the whole cosmological amplitudes are also derived and this shows some advantages to directly study the differential equations with time integrals.

Bio: Jiang Xuhang is now a post-doc at Institute of Theoretical Physics, Chinese Academy of Sciences. He obtained his Ph.D. from Peking University in 2023. He mainly works on the symbology and special functions of Feynman integrals from amplitudes and correlators.