Time: 10:00am, April 30 (Thur.), 2026

Venue: Rm 401, Kavli ITS Meeting Room, No. 7 Building, Zhong-Guan-Cun Campus of UCAS

Speaker: Yunfeng Jiang (Southeast Univ.)

Abstract:

The torus partition function of a TTbar-deformed conformal field theory (CFT) plays an important role in the study of TTbar deformation. This function is modular invariant, enabling a harmonic analysis on the Poincaré upper half-plane. Such an analysis provides a natural and powerful framework for computing and analyzing this quantity. In this talk, I will first review the TTbar-deformed partition function and the basics of harmonic analysis on the Poincaré upper half-plane. I will then explain how to expand the CFT partition function in terms of Maass waveforms, which are functions that are modular invariant and transform in a particularly simple manner under TTbar deformation. Next, I will discuss how this approach allows us to compute the deformed partition function at finite values of the deformation parameter, thereby revealing its analytic structure. Finally, I will show that harmonic analysis offers a natural analytic continuation that defines the partition function beyond the Hagedorn singularity.

【个人简介】
江云峰，东南大学物理学院与丘成桐中心教授。2011年中山大学本科毕业，2012年于法国巴黎高等师范学院获得硕士学位，2015年于法国索邦大学（原巴黎第六大学）获得理论物理博士学位。2015 - 2021年分别在苏黎世联邦理工学院（ETH Zurich）以及欧洲核子研究中心（CERN）任博士后研究员。2021年入职东南大学物理学院与丘成桐中心。主要研究可积系统、量子场论与量子引力理论。