论文标题
重力动力学在概率分布的子空间上的投影：无卷曲的高斯ANSATZ
Projection of the gravitational dynamics on a subspace of probability distributions: curl-free Gaussian ansatz
论文作者
论文摘要
我们提出了一种新方法，以模拟大规模结构的重力动力学。我们遵循近似子空间内的位移和速度场的概率分布的演变，而不是将运动方程求解到有限的扰动顺序或建筑现象学模型。将精确的运动方程与其完整的非线性保持相关，这提供了超越外壳交叉的非驱动方案。专注于最简单的无卷曲高斯ANSATZ用于位移和速度场的最简单情况，我们发现非线性尺度上功率谱的截断直接来自运动方程。这导致了密度功率谱的截断的Zeldovich近似，但截断未设置为先验的截断，并且具有不同的功率光谱，用于位移和速度场。其自动功率谱的积极性也来自运动方程。尽管仅在BAO尺度上恢复了密度功率谱，但预测的密度相关函数与来自BAO级别的$ 2 \％$内的数值仿真相符，至$ 7 H^{ - 1} {\ rm MPC} $ z \ egeq 0.35 $，没有任何免费参数，而无需任何免费参数。
We present a new approach to model the gravitational dynamics of large-scale structures. Instead of solving the equations of motion up to a finite perturbative order or building phenomenological models, we follow the evolution of the probability distribution of the displacement and velocity fields within an approximation subspace. Keeping the exact equations of motion with their full nonlinearity, this provides a nonperturbative scheme that goes beyond shell crossing. Focusing on the simplest case of a curl-free Gaussian ansatz for the displacement and velocity fields, we find that truncations of the power spectra on nonlinear scales directly arise from the equations of motion. This leads to a truncated Zeldovich approximation for the density power spectrum, but with a truncation that is not set a priori and with different power spectra for the displacement and velocity fields. The positivity of their auto power spectra also follows from the equations of motion. Although the density power spectrum is only recovered up to a smooth drift on BAO scales, the predicted density correlation function agrees with numerical simulations within $2\%$ from BAO scales down to $7 h^{-1} {\rm Mpc}$ at $z \geq 0.35$, without any free parameter.
