Time: 10:00-11:30, 2023/11/08

Location: 401, 7th building, KITS

Speaker: Wenliang Li (SYSU, Guangzhou and Zhongshan Ur)

Abstract:

In the bootstrap studies, the self-consistency constraints usually lead to underdetermined systems. Additional assumptions are needed, such as basic principles or educated ansatz. In this talk, I will discuss the bootstrap study of Green’s functions G_n using Dyson-Schwinger equations. I will first explain why the nonperturbative Dyson-Schwinger equations are underdetermined. A naïve truncation scheme can lead to convergent but wrong results. I will discuss two recent resolutions. The first one is based on the large-n asymptotic behavior, and the second one makes use of the null state condition. If the Green’s functions G_n admit analytic continuation to complex values of n, the two different approaches are unified by the novel principle of minimal singularity.