标题： 场级推理与大尺度上常规分析的等价性 显示英文标题

标题： Equivalence of the field-level inference and conventional analyses on large scales

摘要： 我们研究了一个简单的设置，在实空间中存在暗物质晕，线性密度场的振幅$A$是唯一的自由宇宙学参数。 我们表明，在大尺度上，欧拉微扰理论足以描述该系统，计算出主导的$n$-点函数并进行联合功率谱、三阶谱和四阶谱分析。 除了对打破$A$与线性偏差之间的退化至关重要的三阶谱外，我们发现加入四阶谱仅将$A$的误差减少$20-30\%$。 我们在同一设置下的联合分析结果与最近的场级分析结果高度一致。 这意味着在大尺度上的场级推断不会从欧拉核或超过三阶谱的高阶$n$-点函数之外的大位移中获得显著信息。 我们进一步提供了证据，表明在两种方法中，误差条对分析中使用的最大波数的依赖关系是相同的。 我们的结果与一些基于微扰正向建模的无似然推断的近期联合功率谱和三阶谱分析存在分歧。 我们讨论了这种差异的可能原因，并强调解决这一问题的重要性，以在基于微扰理论的宇宙学分析中获得最佳结果。 显示英文摘要

摘要： We study a simple setup with dark matter halos in real space, with the amplitude of the linear density field $A$ as the only free cosmological parameter. We show that Eulerian perturbation theory is adequate for describing this system on large scales, compute the leading $n$-point functions and perform a joint power spectrum, bispectrum and trispectrum analysis. Beyond the bispectrum which is crucial for breaking the degeneracy between $A$ and the linear bias, we find that addition of the trispectrum reduces the error on $A$ by only $20-30\%$. Our results for the joint analysis are in good agreement with recent field-level analyses in the same setup. This implies that the field-level inference on large scales does not get significant information from large displacements beyond those in Eulerian kernels or higher-order $n$-point functions beyond the trispectrum. We provide further evidence for this showing that the dependence of the error bars on the maximum wavenumbers used in the analysis is the same in the two approaches. Our results are in disagreement with some of the recent joint power spectrum and bispectrum analyses using likelihood-free inference based on perturbative forward modeling. We discuss a possible origin of this discrepancy and highlight the importance of resolving it in order to have the optimal results in cosmological analyses based on perturbation theory.