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arXiv 1502.02034hep-thmath-phmath.AGmath.COmath.MP
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非平面壳上图

Non-Planar On-Shell Diagrams

Sebastian Franco, Daniele Galloni, Brenda Penante, Congkao Wen

摘要:

我们发起了一个系统的研究非平面上壳图N=4 SYM和开发强大的技术这样做。我们引入规范变量推广面变量,使dlog形式的壳形式明确。我们取得了重大进展的任意壳图的一般分类的两类组合对象:广义匹配和拟阵多面体。我们提出了一个边界测量,连接一般的壳图的格拉斯曼。我们的建议表现出两个重要的和非平凡的性质:积极的平面的情况下,它匹配的组合描述的广义拟阵多面体的图。有趣的是,非平面图表现出新颖的现象,如出现的约束Plucker坐标超出Plucker关系删除边时,这是整齐地捕捉到的广义匹配和拟阵多面体。这种行为与壳上形式的一种新型极点的存在有关,在这种极点处,Plucker坐标的组合消失。最后,我们介绍了一个处方,适用于超越MHV的情况下,直接从图中写入作为未成年人的函数的壳形式。

英文摘要:

We initiate a systematic study of non-planar on-shell diagrams in N=4 SYM and develop powerful technology for doing so. We introduce canonical variables generalizing face variables, which make the dlog form of the on-shell form explicit. We make significant progress towards a general classification of arbitrary on-shell diagrams by means of two classes of combinatorial objects: generalized matching and matroid polytopes. We propose a boundary measurement that connects general on-shell diagrams to the Grassmannian. Our proposal exhibits two important and non-trivial properties: positivity in the planar case and it matches the combinatorial description of the diagrams in terms of generalized matroid polytopes. Interestingly, non-planar diagrams exhibit novel phenomena, such as the emergence of constraints on Plucker coordinates beyond Plucker relations when deleting edges, which are neatly captured by the generalized matching and matroid polytopes. This behavior is tied to the existence of a new type of poles in the on-shell form at which combinations of Plucker coordinates vanish. Finally, we introduce a prescription, applicable beyond the MHV case, for writing the on-shell form as a function of minors directly from the graph.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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