Constructing perturbation theory kernels for large-scale structure in generalized cosmologies

标准扰动理论用于相互作用暗物质领域宇宙学 I：爱因斯坦-德西特核的失效

Standard Perturbation Theory for Interacting Dark Sector cosmologies I: Breakdown of Einstein de Sitter kernels

本文发展了不依赖爱因斯坦-德西特近似的一阶标准扰动理论框架，揭示了弱相互作用导致扰动核时间依赖性增强，从而破坏了传统ΛCDM分析中的爱因斯坦-德西特近似，对暗物质领域模型的非线性修正进行了系统性研究。

Clustering in Massive Neutrino Cosmologies via Eulerian Perturbation Theory

We introduce an Eulerian Perturbation Theory to study the clustering of tracers for cosmologies in the presence of massive neutrinos. Our approach is based on mapping recently-obtained Lagrangian Perturbation Theory results to the Eulerian framework. We add Effective Field Theory counterterms, IR-resummations and a biasing scheme to compute the one-loop redshift-space power spectrum. To assess our predictions, we compare the power spectrum multipoles against synthetic halo catalogues from the Quijote simulations, finding excellent agreement on scales $k\lesssim 0.25 \,h \text{Mpc}^{-1}$. One c…

Fast computation of non-linear power spectrum in cosmologies with massive neutrinos

We compute 1-loop corrections to the redshift space galaxy power spectrum in cosmologies containing additional scales, and hence kernels different from Einstein-de Sitter (EdS). Specifically, our method is tailored for cosmologies in the presence of massive neutrinos and some modified gravity models; in this article we concentrate on the former case. The perturbative kernels have contributions that we notice appear either from the logarithmic growth factor $f(k,t)$, which is scale-dependent because of the neutrino free-streaming, or from the failure of the commonly used approximation $f^2=Ω_m$…

广义爱因斯坦-德西特宇宙学中的宇宙学扰动理论

Cosmological perturbation theory using generalized Einstein de Sitter cosmologies

本文推广爱因斯坦-德西特宇宙的扰动理论至广义EdS模型，推导解析核，并简化标准宇宙学模型中的单环功率谱修正，仅用少量有效增长率参数即可近似。

Loop corrections to the power spectrum for massive neutrino cosmologies with full time- and scale-dependence

Loop corrections to the power spectrum are frequently computed using approximate non-linear kernels adopted from an Einstein de-Sitter (EdS) cosmology. We present an algorithm that allows us to take the full time- and scale-dependence of the underlying fluid dynamics into account, and apply it to assess the impact of neutrino free-streaming on the 1- and 2-loop matter power spectrum. Neutrino perturbations are described by a hybrid Boltzmann/two-fluid model, that we show to agree with the CLASS Boltzmann solution at the linear level when using an appropriate effective neutrino sound velocity. …

Nonlinear evolution of initially biased tracers in modified gravity

In this work we extend the perturbation theory for modified gravity (MG) in two main aspects. First, the construction of matter overdensities from Lagrangian displacement fields is shown to hold in a general framework, allowing us to find Standard Perturbation Theory (SPT) kernels from known Lagrangian Perturbation Theory (LPT) kernels. We then develop a theory of biased tracers for generalized cosmologies, extending already existing formalisms for $Λ$CDM. We present the correlation function in Convolution-LPT and the power spectrum in SPT for $Λ$CDM, $f(R)$ Hu-Sawicky, and DGP braneworld mode…