发表机构
Middle East Technical University; University of Chicago（中东理工大学; 芝加哥大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本综述系统阐述如何将散射振幅方法（旋量螺旋度、壳上递推、双拷贝等）推广至宇宙学关联函数，通过动量空间框架揭示其解析结构，并连接暴胀观测量与宇宙学光学定理、自举及对撞机等前沿纲领。
AI 中文摘要
宇宙微波背景辐射和大尺度结构背后的原初统计信息，编码在晚期宇宙关联函数中（由宇宙波函数的系数构造）。它们是宇宙学中最接近S矩阵的类比物，但标准的S矩阵工具并不直接适用。本综述解释了现代散射振幅纲领（旋量螺旋度、壳上递推、双拷贝、正几何和广义幺正性）如何被扩展到宇宙学，并通过单一解析延拓扩展到欧几里得反德西特空间，在那里同样的对象作为全息边界关联函数出现，且通常计算最为简洁。组织框架是晚期时间边界上的动量空间，其中原初统计信息最为简单，且外腿的总能量（其动量大小之和）控制解析结构。在总能量奇点处，平直空间散射振幅显现。我们从波动方程出发发展这一工具包，并用它计算树级标量、规范场和引力子关联函数，揭示不同自旋和维度之间的关系。然后我们展示如何利用宇宙学多面体、壳上递推和曲率空间版本的双拷贝来绕过体积分，再将讨论扩展到圈、软极限、跃迁振幅和（A）dS切割规则。最后，我们将这些结构与暴胀观测量及三个相关纲领联系起来：宇宙学光学定理、宇宙学自举和宇宙学对撞机。我们以当前前沿的地图和一组开放且有趣的问题作为结论。
英文摘要
The primordial statistics underlying the CMB and large-scale structure are encoded in late-time cosmological correlation functions (constructed from the coefficients of the wavefunction of the universe). They are the closest analogue cosmology has to an $S$-matrix, yet the standard $S$-matrix toolkit does not directly apply. This review explains how the modern scattering-amplitudes program (spinor helicity, on-shell recursion, the double copy, positive geometry, and generalized unitarity) has nevertheless been extended to cosmology and, through a single analytic continuation, to Euclidean anti-de Sitter space, where the same objects appear as holographic boundary correlators and are often cleanest to compute. The organizing framework is momentum space on the late-time boundary, where the primordial statistics are simplest and where the total energy of the external legs, the sum of their momentum magnitudes, controls the analytic structure. At the total-energy singularity, the flat-space scattering amplitude emerges. We develop this toolkit starting from the wave equation and use it to compute tree-level scalar, gauge-field, and graviton correlators, exposing relations across spins and dimensions. We then show how bulk integrals can be bypassed using cosmological polytopes, on-shell recursion, and curved-space versions of the double copy, before extending the discussion to loops, soft limits, transition amplitudes, and (A)dS cutting rules. Finally, we connect these structures to inflationary observables and to three allied programs: the cosmological optical theorem, the cosmological bootstrap, and the cosmological collider. We conclude with a map of the current frontier and a set of open and interesting problems.
Comments40 pages, 11 figures
