报告题目：Two-loop NMHV octagons from Qbar equations

报告人：张弛（ 中科院理论所）

报告时间：2019 年 12月2日（ 周一） 15： 00 ~ 16： 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 SYM theory, which arise from the dual superconformal anomaly of this theory. Perturbatively the equations express the derivatives of amplitudes at a given loop order as integrals of lower-loop amplitudes with more legs. I will show how to use Qbar equations to calculate the differential of two-loop n-point NMHV amplitudes by considering a particular example n=8 , which is the first multi-loop amplitudes involving algebraic letters. At last, I will comment on 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 andParticle 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 formsand amplitudes from subspaces, JHEP 08 (2018) 040 [arXiv:1803.11302].

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

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