标题： 宇宙密度分布函数的演化 显示英文标题

标题： Evolution of the cosmological density distribution function

摘要： 我们基于精确的统计处理方法，提出了一种新的计算方法，用于研究宇宙密度场的一点概率分布函数（PDF）的演化。利用Chapman-Kolmogorov方程和二阶欧拉扰动理论，我们将初始密度分布传播到非线性区域。我们的计算得到了矩生成函数，从而可以方便地推导出PDF的偏斜度到二阶精度。我们发现初始扰动谱存在一种新的依赖关系。我们将我们的结果与其他近似方法得到的一点PDF以及N体模拟进行了比较。我们发现我们的分布能够准确地模拟暗物质一点PDF的演化。 显示英文摘要

摘要： We present a new calculation for the evolution of the 1-point Probability Distribution Function (PDF) of the cosmological density field based on an exact statistical treatment. Using the Chapman-Kolmogorov equation and second-order Eulerian perturbation theory we propagate the initial density distribution into the nonlinear regime. Our calculations yield the moment generating function, allowing a straightforward derivation of the skewness of the PDF to second order. We find a new dependency on the initial perturbation spectrum. We compare our results with other approximations to the 1-pt PDF, and with N-body simulations. We find that our distribution accurately models the evolution of the 1-pt PDF of dark matter.