A journey through nine loops, cluster algebras and Higgs amplitudes

by 颂 何 (中国科学院理论物理研究所)

Wednesday 30 Sept 2026, 15:10 → 16:10 Asia/Shanghai

B105 (CHEP)

How far can we determine scattering amplitudes without the need for Feynman diagrams or loop integrations? Planar N=4 super-Yang–Mills (sYM) provides an ideal laboratory for uncovering the mathematical structures and physical relations that make this possible. I will introduce a computational framework dubbed “automated symbol bootstrap,” whose symmetry-adapted algorithm has yielded nine-loop symbols for six-gluon MHV and NMHV amplitudes and, via antipodal duality, three-point form factors of the stress-tensor multiplet. These results offer new clues to the patterns that organize perturbation theory across loop orders.

Turning to four-point form factors, I will present our construction of a new cluster algebra for their symbol alphabet, and discuss how dualities and physical limits connect seemingly different observables. Finally, new results for Higgs-plus-four-gluon amplitudes at maximal transcendental weight reveal how some of this simplicity extends beyond this supersymmetric laboratory.

Bio:
何颂，中国科学院理论物理研究所研究员、新基石研究员。主要从事量子场论、弦论与量子引力研究，近年来尤其关注散射振幅等物理量的新计算方法、数学结构及其应用，探索基础物理与数学的交叉问题。与合作者共同提出了 Cachazo–何–袁（CHY）散射振幅形式，揭示了场论与弦论散射的几何和组合结构，并在高圈计算、精确求解及规范场、引力与弦论的对偶关系等方向取得了一系列重要成果。