Cosmological perturbations for two cold fluids in $\Lambda$CDM

Abstract

The cosmic large-scale structure of our Universe is comprised of baryons and cold dark matter (CDM). Yet it is customary to treat these two components as a combined single-matter fluid with vanishing pressure, which is justified only for sufficiently large scales and late times. Here we go beyond the single-fluid approximation and develop the perturbation theory for two gravitationally coupled fluids while still assuming vanishing pressure. We mostly focus on perturbative expansions in powers of $D$ (or $D_{+}$), the linear structure growth of matter in a $\Lambda$CDM Universe with cosmological constant $\Lambda$. We derive in particular (1) explicit recursion relations for the two fluid densities, (2) complementary all-order results in the Lagrangian-coordinates approach, as well as (3) the associated component wavefunctions in a semi-classical approach to cosmic large-scale structure. In our companion paper (Hahn et al. 2020) we apply these new theoretical results to generate novel higher-order initial conditions for cosmological hydrodynamical simulations.

arXiv comment15 pages + appendices, one figure, MNRAS in press

References in corpus (90)

• The 6dF Galaxy Survey: Baryon Acoustic Oscillations and the Local Hubble Constant
• The Baryon Oscillation Spectroscopic Survey of SDSS-III
• Large-Scale Structure of the Universe and Cosmological Perturbation Theory
• Ultralight scalars as cosmological dark matter
• The WiggleZ Dark Energy Survey: mapping the distance-redshift relation with baryon acoustic oscillations
• Multi-scale initial conditions for cosmological simulations
• Large-Scale Galaxy Bias
• Transients from Initial Conditions in Cosmological Simulations
• Renormalized Cosmological Perturbation Theory
• Resumming Cosmological Perturbations via the Lagrangian Picture: One-loop Results in Real Space and in Redshift Space
• Relative velocity of dark matter and baryonic fluids and the formation of the first structures
• The Lyman-alpha Forest Power Spectrum from the Sloan Digital Sky Survey
• Non-Linear Evolution of the Bispectrum of Cosmological Perturbations
• Convolution Lagrangian perturbation theory for biased tracers
• Generation of Vorticity and Velocity Dispersion by Orbit Crossing
• The Lagrangian-space Effective Field Theory of Large Scale Structures
• Flowing with Time: a New Approach to Nonlinear Cosmological Perturbations
• Contact Hamiltonian Mechanics
• Tracing the Dark Matter Sheet in Phase Space
• Reconstruction of the early Universe as a convex optimization problem
• Nonlinear Perturbation Theory Integrated with Nonlocal Bias, Redshift-space Distortions, and Primordial Non-Gaussianity
• Lagrangian theory of gravitational instability of Friedman-Lemaitre cosmologies - generic third-order model for non-linear clustering
• Newtonian Cosmology in Lagrangian Formulation: Foundations and Perturbation Theory
• Growth of Linear Perturbations before the Era of the First Galaxies
• The One-Loop Matter Bispectrum in the Effective Field Theory of Large Scale Structures
• Cosmological perturbation theory at three-loop order
• Analytic Prediction of Baryonic Effects from the EFT of Large Scale Structures
• Accurate initial conditions for cosmological N-body simulations: Minimizing truncation and discreteness errors
• Coarse-Grained Cosmological Perturbation Theory
• Recursive Solutions of Lagrangian Perturbation Theory
• Lagrangian perturbations and the matter bispectrum I: fourth-order model for non-linear clustering
• Lagrangian perturbation theory at one loop order: successes, failures, and improvements
• Schrödinger method as N-body double and UV completion of dust
• Numerical and Perturbative Computations of the Fuzzy Dark Matter Model
• Structure formation with massive neutrinos: going beyond linear theory
• The effect of relative velocity and density perturbations between baryons and dark matter on the clustering of galaxies
• Time-analyticity of Lagrangian particle trajectories in ideal fluid flow
• Improving Initial Conditions for Cosmological $N$-Body Simulations
• Resummed propagators in multi-component cosmic fluids with the eikonal approximation
• Higher-order initial conditions for mixed baryon-CDM simulations
• On the signature of the baryon-dark matter relative velocity in the two and three-point galaxy correlation functions
• An analytic implementation of the IR-resummation for the BAO peak
• Third-order Perturbation Theory With Non-linear Pressure
• How closely do baryons follow dark matter on large scales?
• The Theory of Caustics and Wavefront Singularities with Physical Applications
• Cosmological perturbation theory for baryons and dark matter I: one-loop corrections in the RPT framework
• GridSPT: Grid-based calculation for perturbation theory of large-scale structure
• Response function of the large-scale structure of the universe to the small scale inhomogeneities
• Solving the Vlasov equation in two spatial dimensions with the Schrödinger method
• How to add massive neutrinos to your $\Lambda$CDM simulation -- extending cosmology rescaling algorithms
• The Effective Field Theory of Large-Scale Structure in the presence of Massive Neutrinos
• Chasing the non-linear evolution of matter power spectrum with numerical resummation method: solution of closure equations
• A Lagrangian Perturbation Theory in the presence of massive neutrinos
• Approximating tunneling rates in multi-dimensional field spaces
• Fully relativistic treatment of light neutrinos in $N$-body simulations
• Constraining the Baryon-Dark Matter Relative Velocity with the Large-Scale 3-Point Correlation Function of the SDSS BOSS DR12 CMASS Galaxies
• General relativistic weak-field limit and Newtonian N-body simulations
• Post-collapse perturbation theory in 1D cosmology -- beyond shell-crossing
• Lagrangian perturbations and the matter bispectrum II: the resummed one-loop correction to the matter bispectrum
• How smooth are particle trajectories in a $\Lambda$CDM Universe?
• Biased Tracers of Two Fluids in the Lagrangian Picture
• Cosmic propagators at two-loop order
• Observational constraints on cosmic neutrinos and dark energy revisited
• Large-scale structure perturbation theory without losing stream crossing
• Shell-crossing in quasi-one-dimensional flow
• Vlasov-Poisson in 1D for initially cold systems: post-collapse Lagrangian perturbation theory
• Structure formation beyond shell-crossing: nonperturbative expansions and late-time attractors
• Lagrangian cosmological perturbation theory at shell-crossing
• The Intrinsic Matter Bispectrum in $\Lambda$CDM
• A coarse grained perturbation theory for the Large Scale Structure, with cosmology and time independence in the UV
• Cosmological $N$-body simulations including radiation perturbations
• More accurate simulations with separate initial conditions for baryons and dark matter
• Semiclassical path to cosmic large-scale structure
• On Second-order Perturbation Theories of Gravitational Instability in Friedmann-Lemaitre Models
• Trajectories of point particles in cosmology and the Zel'dovich approximation
• Renormalization-group flow of the effective action of cosmological large-scale structures
• Accurate initial conditions in mixed Dark Matter--Baryon simulations
• Fast simulations of cosmic large-scale structure with massive neutrinos
• Unveiling the singular dynamics in the cosmic large-scale structure
• A hierarchical field-level inference approach to reconstruction from sparse Lyman-$\alpha$ forest data
• Gravitational instability via the Schrodinger equation
• Perturbation theory in Lagrangian hydrodynamics for a cosmological fluid with velocity dispersion
• Lagrangian theory for cosmic structure formation with vorticity: Newtonian and post-Friedmann approximations
• Resummed Kinetic Field Theory: general formalism and linear structure growth from Newtonian particle dynamics
• Quasi-spherical collapse of matter in $\Lambda$CDM
• Asymptotic expansions for the Large Scale Structure
• Wave-mechanics and the adhesion approximation
• Evolution of density perturbations in a realistic universe
• Resummed Kinetic Field Theory: Using Mesoscopic Particle Hydrodynamics to Describe Baryonic Matter in a Cosmological Framework
• Resummed Kinetic Field Theory: a model of coupled baryonic and dark matter

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• A new analysis of galaxy 2-point functions in the BOSS survey, including full-shape information and post-reconstruction BAO
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• Accurate initial conditions for cosmological N-body simulations: Minimizing truncation and discreteness errors
• Higher-order initial conditions for mixed baryon-CDM simulations
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• SPICE: the connection between cosmic reionisation and stellar feedback in the first galaxies
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