IBP & Differential Equations in de Sitter Spacetime - From Tree to Loop

by 家麒 陈 (中国石油大学（北京）)

Monday 22 Jun 2026, 14:00 → 15:00 Asia/Shanghai

B105 (CHEP)

Quantum field theory in de Sitter spacetime has important phenomenological applications in inflationary cosmology. In this talk, I will present how Integration-By-Parts (IBP) reduction and differential equation methods can be extended to de Sitter spacetime (with Hankel function in the integrand), and highlight some practical and elegant mathematical properties of de Sitter correlation functions. We will see that for time integrals, a few simple general formulas are sufficient to iteratively reduce all integrals to master integrals, yielding dlog differential equations along with their analytic boundary conditions. For loop-level calculations involving both time and loop momentum integrals, we find that the IBP system splits into independent subsystems based on the parity of the indices. Furthermore, based on fibration intersection theory, we conjecture and verify how to construct dlog integrands to obtain dlog differential equations in the de Sitter case.

报告人简介：陈家麒，本科毕业于浙江大学，博士就读于北京大学理论物理专业，后于高能所、北京计算科学研究中心从事博士后工作，2025年入职中国石油大学（北京）讲师。主要研究费曼积分的数学结构与计算方法，过去研究较多集中于平直时空费曼积分的正则微分方程以及intersection theory在其中的应用，近期研究兴趣集中于发展弯曲时空微扰场论的计算方法。