论文标题
小盒子的准确预测：通过zel'dovich近似抑制方差
Accurate predictions from small boxes: variance suppression via the Zel'dovich approximation
论文作者
论文摘要
模拟已成为必不可少的工具，可以准确地建模在星系调查中测量的可观察物，但是如果需要大量的动态范围，则可能会很昂贵。我们描述了如何将Lagrangian扰动理论模型与N体模拟相结合，以减少有限的计算量在控制变体背景下模拟中集合平均属性预测中的影响。特别是，我们使用的是，在任何模拟的初始条件生成期间计算出的Zel'Dovich位移与最终密度场密切相关。由于可以用任意精度计算这些位移的所有偏见示踪剂的相关器，因此将Zel'Dovich的“仿真”与N体实现配对，可以使功率谱或相关函数估计的样本方差减少一百倍。 Zel'Dovich控制变体可以将物质或示踪剂场模拟器准确地扩展到比以前更大的尺度上，并改善了固有限制在较小体积的模拟中的统计数据的测量值，例如银河形成和复离的流体动力学模拟。
Simulations have become an indispensable tool for accurate modelling of observables measured in galaxy surveys, but can be expensive if very large dynamic range in scale is required. We describe how to combine Lagrangian perturbation theory models with N-body simulations to reduce the effects of finite computational volume in the prediction of ensemble average properties in the simulations within the context of control variates. In particular we use the fact that Zel'dovich displacements, computed during initial condition generation for any simulation, correlate strongly with the final density field. Since all the correlators of biased tracers can be computed with arbitrary precision for these displacements, pairing the Zel'dovich `simulation' with the N-body realization allows hundredfold reductions in sample variance for power spectrum or correlation function estimation. Zel'dovich control variates can accurately extend matter or tracer field emulators to larger scales than previously possible, as well as improving measurements of statistics in simulations which are inherently limited to small volumes, such as hydrodynamical simulations of galaxy formation and reionization.
