报告人：　张弛（ 中科院理论所）
报告时间：2019-12-02 15:00
报告地点：北洋园校区理学院32教256

报告摘要： 

Qbar equations are a set of first-order differential equations obeyed by the S-matrix of planar N=4 SYMtheory, which arise from the dual superconformal anomaly of this theory. Perturbatively the equations express thederivatives of amplitudes at a given loop order as integrals of lower-loop amplitudes with more legs. I will showhow to use Qbar equations to calculate the differential of two-loop n-point NMHV amplitudes by considering aparticular example n=8 , which is the first multi-loop amplitudes involving algebraic letters. At last, I will commenton the last entry conditions to which all NMHV loop amplitudes should subject. 

报告人简历： 

张弛2015年本科毕业于天津大学， 现博士就读于中科院理论所， 预计2020年获博士学位。 

代表作： 

【1】 C. Zhang, Z. Li and S. He, Two-loop Octagons, Algebraic Letters and Qbar Equations, [arXiv:1911.01290]. 

【2】 Z. Li and C. Zhang, Moduli Space of Paired Punctures, Cyclohedra and Particle Pairs on a Circle, JHEP 05 (2019)029 [arXiv:1812.10727]. 

【3】 S. He and C. Zhang, Notes on Scattering Amplitudes as Differential Forms, JHEP 10 (2018) 054 [arXiv:1807.11051]. 

【4】 S. He, G. Yan, C. Zhang and Y. Zhang, Scattering forms, worldsheet forms and amplitudes from subspaces, JHEP08 (2018) 040 [arXiv:1803.11302]. 

【5】 M. Yu, C. Zhang and Y. Zhang, One loop amplitude from null string, JHEP06 (2017) 051 [arXiv:1704.01290]