Non-linear evolution of f(R) cosmologies I: methodology

By H. Oyaizu. 2008

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We introduce the method and the implementation of a cosmological simulation of a class of metric-variation f(R) models that accelerate the cosmological expansion without a cosmological constant and evade solar-system bounds of small-field deviations to general relativity. Such simulations are shown to reduce to solving a non-linear Poisson equation for the scalar degree of freedom introduced by the f(R) modifications. We detail the method to efficiently solve the non-linear Poisson equation by using a Newton-Gauss-Seidel relaxation scheme coupled with multigrid method to accelerate the convergence. The simulations are shown to satisfy tests comparing the simulated outcome to analytical solutions for simple situations, and the dynamics of the simulations are tested with orbital and Zeldovich collapse tests. Finally, we present several static and dynamical simulations using realistic cosmological parameters to highlight the differences between standard physics and f(R) physics. In general, we find that the f(R) modifications result in stronger gravitational attraction that enhances the dark matter power spectrum by ~20% for large but observationally allowed f(R) modifications. More detailed study of the non-linear f(R) effects on the power spectrum are presented in a companion paper.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/482ca5a59536a62c1db5103e2622389c7e3375fc

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Citations in the corpus

ECOSMOG: an Efficient COde for Simulating MOdified Gravity (2011, methodology): “There are two such codes known to us to date: one is that of Oyaizu [15], which has been applied to f(R) gravity [16, 17] and the DGP model [18]; the other is a modified MLAPM code [19] written by one of the authors [20] and which has been applied to chameleon theories [21], f(R) gravity [22], coupl”
Cosmological tests of modified gravity (2015, background): “There have been significant progress in developing N-body simulations [275, 276, 277, 278, 279, 280, 281, 282, 283, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298].”
Modified Gravity-GADGET: A new code for cosmological hydrodynamical simulations of modified gravity models (2013, methodology): “For viable models with fR ≪ 1 and in the quasistatic approximation, i.e. assuming |∇fR| ≫ ∂fR∂t , the field equation for fR is given by (see e.g. Oyaizu 2008) ∇2fR = 1 3c2 (δR − 8πGδρ) , (2) where we have here restored factors of the speed of light c, and δρ and δR are the perturbations in the…”
Accurate halo-model matter power spectra with dark energy, massive neutrinos and modified gravitational forces (2016, background): “Determining when this condition is satisfied in a cosmological context can be achieved using simulations (Oyaizu 2008; Zhao et al. 2011; Li et al. 2012; Puchwein et al. 2013; Llinares et al. 2014; summarized by Winther et al. 2015) or via direct calculations in idealized situations with symmetry…”
Hydrodynamical N-body simulations of coupled dark energy cosmologies (2008, background): “…& Peebles (2005), Stabenau & Jain (2006), Kesden & Kamionkowski (2006), Springel & Farrar (2007), Laszlo & Bean (2008), Sutter & Ricker (2008), Oyaizu (2008), Keselman, Nusser & Peebles (2009), but to our knowledge Macciò et al. (2004) is the only work to date focusing on the properties of…”