标题： 经典力学路径积分的宇宙结构及其与标准微扰理论的比较 显示英文标题

标题： Cosmic structure from the path integral of classical mechanics and its comparison to standard perturbation theory

摘要： 我们研究在相空间中一个$N$粒子系综的路径积分形式框架下的宇宙结构形成，称为重求和动力学场理论（RKFT），直到一环微扰阶。 特别是，我们计算了密度对比的功率谱、动量密度的散度和旋度以及应力张量的任意$n$点累积量。 与早期工作不同，我们提出了一种不同的初始条件采样方法，具有高斯初始相空间密度。 这样做，我们准确地再现了欧拉标准微扰理论（SPT）在一次环阶的相应结果，表明以前发现的偏差可以完全归因于之前采样方法中的不一致。 由于与SPT不同，完整的相空间描述并不假设Vlasov层次结构的截断，我们的研究结果表明，需要非微扰技术来准确捕捉宇宙结构形成的物理过程。 显示英文摘要

摘要： We investigate cosmic structure formation in the framework of a path-integral formulation of an $N$-particle ensemble in phase space, dubbed Resummed Kinetic Field Theory (RKFT), up to one-loop perturbative order. In particular, we compute power spectra of the density contrast, the divergence and curl of the momentum density and arbitrary $n$-point cumulants of the stress tensor. In contrast to earlier works, we propose a different method of sampling initial conditions, with a Gaussian initial phase-space density. Doing so, we exactly reproduce the corresponding results from Eulerian standard perturbation theory (SPT) at one-loop order, showing that formerly found deviations can be fully attributed to inconsistencies in the previous sampling method. Since, in contrast to SPT, the full phase-space description does not assume a truncation of the Vlasov hierarchy, our findings suggest that non-perturbative techniques are required to accurately capture the physics of cosmic structure formation.