Abstract
We introduce the method and the implementation of a cosmological simulation of a class of metric-variation 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 nonlinear Poisson equation for the scalar degree of freedom introduced by the modifications. We detail the method to efficiently solve the nonlinear Poisson equation by using a Newton-Gauss-Seidel relaxation scheme coupled with the 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 physics. In general, we find that the modifications result in stronger gravitational attraction that enhances the dark matter power spectrum by for large but observationally allowed modifications. A more detailed study of the nonlinear effects on the power spectrum are presented in a companion paper.
4 More- Received 17 July 2008
DOI:https://doi.org/10.1103/PhysRevD.78.123523
©2008 American Physical Society