论文标题
超越对数正态近似：一般模拟方案
Beyond the Lognormal Approximation: a General Simulation Scheme
论文作者
论文摘要
我们提出一个公共代码，以生成具有任意概率分布函数（PDF）和任意相关函数的随机字段。该算法是与宇宙学无关的，适用于三维网格上的任何固定随机过程。我们在物质密度字段的情况下实施了它，显示了其比对数正态近似的好处，该近似通常用于宇宙学用于生成模拟目录。我们发现，来自新快速实现的功率谱的协方差比对数字模型的协方差更准确。作为概念的证明，我们还将新的仿真方案应用于拉格朗日位移字段的差异。我们发现，来自相关函数的信息和位移差异的PDF比其他标准分析技术提供了适度的改进，以描述模拟中的粒子场。这表明在这个方向上进一步进展应来自初始物质分布的多尺度或非本地特性。
We present a public code to generate random fields with an arbitrary probability distribution function (PDF) and an arbitrary correlation function. The algorithm is cosmology-independent, applicable to any stationary stochastic process over a three dimensional grid. We implement it in the case of the matter density field, showing its benefits over the lognormal approximation, which is often used in cosmology for generation of mock catalogues. We find that the covariance of the power spectrum from the new fast realizations is more accurate than that from a lognormal model. As a proof of concept, we also apply the new simulation scheme to the divergence of the Lagrangian displacement field. We find that information from the correlation function and the PDF of the displacement-divergence provides modest improvement over other standard analytical techniques to describe the particle field in the simulation. This suggests that further progress in this direction should come from multi-scale or non-local properties of the initial matter distribution.
