Title: The Matter Bispectrum in N-body Simulations with non-Gaussian Initial Conditions Show Chinese title

Title: 具有非高斯初始条件的N体模拟中的物质双谱

Abstract: We present measurements of the dark matter bispectrum in N-body simulations with non-Gaussian initial conditions of the local kind for a large variety of triangular configurations and compare them with predictions from Eulerian Perturbation Theory up to one-loop corrections. We find that the effects of primordial non-Gaussianity at large scales, when compared to Perturbation Theory, are well described by the initial component of the matter bispectrum, linearly extrapolated at the redshift of interest. In addition, we find that, for f_NL=100, the nonlinear corrections due to non-Gaussian initial conditions are of the order of ~3, 4% for generic triangles up to ~20% for squeezed configurations, at any redshift. We show that the predictions of Perturbation Theory at tree-level fail to describe the simulation results at redshift z=0 already at scales corresponding to k ~ 0.02 - 0.08 h/Mpc, depending on the triangle, while one-loop corrections can significantly extend their validity to smaller scales. At higher redshift, one-loop Perturbation Theory provides indeed quite accurate predictions, particularly with respect to the relative correction due to primordial non-Gaussianity. Show Chinese abstract

Abstract: 我们展示了在具有局域型非高斯初条件的N体模拟中，对于大量三角形构型的暗物质双谱测量，并将其与欧拉流体力学一级近似至一阶修正的预测进行了比较。 我们发现，大尺度上原初非高斯性的效应，与流体力学一级近似的对比，可以用物质双谱的初始分量来很好地描述，该分量在线性外推到感兴趣的红移时保持不变。 此外，我们发现，当f_NL=100时，由于非高斯初条件导致的非线性修正对于普通三角形约为~3-4%，而对于压缩构型则高达~20%，在任何红移下均如此。 我们表明，流体力学一级近似的预测在红移z=0时，就已经在对应于k~0.02-0.08 h/Mpc的尺度上无法描述模拟结果，具体取决于三角形的类型，而一阶修正可以显著扩展其有效性到更小的尺度。 在更高红移时，一阶修正的流体力学理论确实提供了相当准确的预测，特别是在相对于原初非高斯性引起的相对修正方面。