The bispectrum is the leading non-Gaussian statistic in Large-Scale Structure (LSS) clustering and encodes the interactions in the underlying field. It is thus an important diagnostic for primordial non-Gaussianity and higher order galaxy biasing. In this paper we present a detailed test and calibration of the matter bispectrum counterterms in the Effective Field Theory of LSS against a suite of $N$-body simulations. We are going beyond previous studies in employing realisation based perturbation theory that allows for a significant reduction in cosmic variance error bars. This enables the measurement of the low-energy constants on large scales before two-loop corrections become relevant, around $k<0.09 h\mathrm{Mpc}^{-1}$ at $z=0$. We also go beyond previous work in using bispectrum propagator terms, i.e. correlators with linear and second order fields, to quantify the two new counterterms in isolation and to establish consistency with the power spectrum counterterm. By investigating the fully non-linear bispectrum, $B_{\mathrm{nnn}}$, as well as the terms $B_{\mathrm{n}11}$ and $B_{\mathrm{n}21}$, we find evidence for the new counterterms deviating from the shape suggested by the UV-limit of the relevant bispectrum contributions. We also show that the commonly used Einstein-de Sitter approximation for the time dependence of the tree-level bispectrum is insufficient for precise studies of the one-loop bispectrum and that it is necessary to use $Λ$CDM growth factors in order to obtain meaningful one-loop counterterm constraints. Finally, we also find evidence for small deviations in the growth factors that arise from time integration inaccuracies in the $N$-body simulations.
Matter bispectrum of large-scale structure with Gaussian and non-Gaussian initial conditions: Halo models, perturbation theory, and a three-shape model
One-Loop Galaxy Bispectrum: Consistent Theory, Efficient Analysis with COBRA, and Implications for Cosmological Parameters
Institute for Theoretical Physics, Utrecht University（乌得勒支大学理论物理研究所）；Center for Theoretical Physics – a Leinweber Institute, Massachusetts Institute of Technology（麻省理工学院莱因韦伯理论物理中心）；Simons Society of Fellows, Simons Foundation（西蒙斯基金会西蒙斯学者协会）；Center for Theoretical Physics, Columbia University（哥伦比亚大学理论物理中心）；Leinweber Institute for Theoretical Physics at Stanford（斯坦福大学莱因韦伯理论物理研究所）；Kavli Institute for Particle Astrophysics and Cosmology（卡弗里粒子天体物理学与宇宙学研究所）；Division of Theoretical Physics, Ruder Bošković Institute（鲁德·博什科维奇研究所理论物理部）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Department of Applied Mathematics and Theoretical Physics, University of Cambridge（剑桥大学应用数学与理论物理系）
Detection of Cosmic Structures using the Bispectrum Phase. II. First Results from Application to Cosmic Reionization Using the Hydrogen Epoch of Reionization Array
Precise Calibration of the One-Loop Trispectrum in the Effective Field Theory of Large Scale Structure
宇宙的大尺度结构（LSS）有可能为宇宙学中尚未解决的问题提供决定性的答案。早期的尝试，它的分析建模集中在使用微扰理论。然而，由引力坍缩引入的小尺度效应不能用微扰来描述，而微扰理论的失败甚至在最大尺度上也能反映出来。大尺度结构的有效场论（Effective Field Theory of Large Scale Structure，EFTofLSS）通过引入小尺度动力学效应的反项，已经成为描述大尺度LSS的一致方法。迄今为止，对EFT的研究主要集中在二点和三点函数上，而对四点函数和三谱的研究较少。三谱探测由非线性聚类、偏置和原始非高斯性引起的立方相互作用，并构成功率谱协方差矩阵的关键元素。在本文中，我们提出了明确的EFT计数器项的单圈三谱校准。具体来说，我们发现明确的证据，非零EFT更正。我们定义了两个单参数ansätze的counterterterm的一个循环传播，并表明，他们提供了一个很好的校正，在尺度低于k~0.07 h/Mpc的残差。然后，我们采取的幅度的线性和二次计算的counterkernels在我们以前的论文上的双谱，并使用它们在其余的counterterterms，建立的一致性的counterterterterms在两个，三个和四个点的功能。我们还表明，通常使用的EdS近似的密度场的增长导致的错误，是相同的幅度的循环校正大尺度上的三谱。
Scale-dependent bias of galaxies and mu-type distortion of the cosmic microwave background spectrum from single-field inflation with a modified initial state
The ACS Fornax Cluster Survey. V. Measurement and Recalibration of Surface Brightness Fluctuations and a Precise Value of the Fornax--Virgo Relative Distance
