Parametrising non-linear dark energy perturbations

Abstract

In this paper, we quantify the non-linear effects from $k$-essence dark energy through an effective parameter $\mu$ that encodes the additional contribution of a dark energy fluid or a modification of gravity to the Poisson equation. This is a first step toward quantifying non-linear effects of dark energy/modified gravity models in a more general approach. We compare our $N$-body simulation results from $k$-evolution with predictions from the linear Boltzmann code $\text{CLASS}$, and we show that for the $k$-essence model one can safely neglect the difference between the two potentials, $\Phi -\Psi$, and short wave corrections appearing as higher order terms in the Poisson equation, which allows us to use single parameter $\mu$ for characterizing this model. We also show that for a large $k$-essence speed of sound the $\text{CLASS}$ results are sufficiently accurate, while for a low speed of sound non-linearities in matter and in the $k$-essence field are non-negligible. We propose a $\tanh$-based parameterisation for $\mu$, motivated by the results for two cases with low ($c_s^2=10^{-7}$) and high ($c_s^2=10^{-4}$) speed of sound, to include the non-linear effects based on the simulation results. This parametric form of $\mu$ can be used to improve Fisher forecasts or Newtonian $N$-body simulations for $k$-essence models.

arXiv comment18 pages, 8 figures. Updated to match version published in JCAP; data available at https://doi.org/10.5281/zenodo.7950666

References in corpus (25)

• Planck 2015 results. XIII. Cosmological parameters
• Efficient Computation of CMB anisotropies in closed FRW models
• The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample
• The Complete Light-curve Sample of Spectroscopically Confirmed Type Ia Supernovae from Pan-STARRS1 and Cosmological Constraints from The Combined Pantheon Sample
• The Cosmic Linear Anisotropy Solving System (CLASS) II: Approximation schemes
• A Dynamical Solution to the Problem of a Small Cosmological Constant and Late-time Cosmic Acceleration
• Essentials of k-essence
• The DESI Experiment Part I: Science,Targeting, and Survey Design
• Revising the Halofit Model for the Nonlinear Matter Power Spectrum
• Cosmology and Fundamental Physics with the Euclid Satellite
• Quintessential inflation
• The Cosmic Linear Anisotropy Solving System (CLASS) I: Overview
• Dark Energy versus Modified Gravity
• A unifying description of dark energy
• Euclid preparation: II. The EuclidEmulator -- A tool to compute the cosmology dependence of the nonlinear matter power spectrum
• General relativity and cosmic structure formation
• gevolution: a cosmological N-body code based on General Relativity
• Relativistic N-body simulations with massive neutrinos
• $k$-evolution: a relativistic N-body code for clustering dark energy
• Relativistic Interpretation of Newtonian Simulations for Cosmic Structure Formation
• Nonlinear cosmological consistency relations and effective matter stresses
• Dark energy perturbations in $N$-body simulations
• Cosmological Perturbation Theory and Structure Formation
• Distinguishing cosmologies using the turn-around radius near galaxy clusters
• 4MOST Scientific Operations

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