论文标题
带有非同伴奇点的积极几何形状和差异形式I
Positive Geometries and Differential Forms with Non-Logarithmic Singularities I
论文作者
论文摘要
积极的几何形式编码在平坦时空中散射幅度的物理和宇宙学中宇宙的波函数的大量模型。它们独特的规范形式提供了这种量子机械可观察物的特征,其特征是仅在正数几何的所有边界上具有对数奇异性。但是,物理可观察物仅适用于一部分理论。因此,了解类似范式在更一般的情况下是否可以构成其结构的基础变得至关重要。在本文中,我们开始对具有非同源性奇异性的差异形式的几何形式表征进行系统研究,重点是带有多个极点的弹性多型和相关的杂粒形式。我们介绍了协变形式和协变量配对的概念。协变形式仅沿给定多层的边界具有极点。此外,它们沿任何边界的领先的劳伦系数仍然是特定边界上的协变形式。尽管与多层配对中的共晶形式与特定(签名的)三角剖分有关,其中伪边界上的两极并不能完全取消,但它们的顺序降低了。如果将其与之相关的多型物体被视为对超平面上较高尺寸的限制,则可以完全表征这些mer态形式。后者的规范形式可以通过协方差限制映射到协变形式或协变合配对中的形式。我们展示了较高维度的几何形状如何决定这些差异形式的结构。最后,我们讨论了这些观念与Jeffrey-Kirwan残基和宇宙学的多面体是如何相关的。
Positive geometries encode the physics of scattering amplitudes in flat space-time and the wavefunction of the universe in cosmology for a large class of models. Their unique canonical forms, providing such quantum mechanical observables, are characterised by having only logarithmic singularities along all the boundaries of the positive geometry. However, physical observables have logarithmic singularities just for a subset of theories. Thus, it becomes crucial to understand whether a similar paradigm can underlie their structure in more general cases. In this paper we start a systematic investigation of a geometric-combinatorial characterisation of differential forms with non-logarithmic singularities, focusing on projective polytopes and related meromorphic forms with multiple poles. We introduce the notions of covariant forms and covariant pairings. Covariant forms have poles only along the boundaries of the given polytope; moreover, their leading Laurent coefficients along any of the boundaries are still covariant forms on the specific boundary. Whereas meromorphic forms in covariant pairing with a polytope are associated to a specific (signed) triangulation, in which poles on spurious boundaries do not cancel completely, but their order is lowered. These meromorphic forms can be fully characterised if the polytope they are associated to is viewed as the restriction of a higher dimensional one onto a hyperplane. The canonical form of the latter can be mapped into a covariant form or a form in covariant pairing via a covariant restriction. We show how the geometry of the higher dimensional polytope determines the structure of these differential forms. Finally, we discuss how these notions are related to Jeffrey-Kirwan residues and cosmological polytopes.