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Speeding up N-body simulations of modified gravity: Chameleon screening models

Bose, Sownak; Li, Baojiu; Barreira, Alexandre; He, Jian-hua; Hellwing, Wojciech A.; Koyama, Kazuya; Llinares, Claudio; Zhao, Gong-Bo

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Authors

Sownak Bose

Alexandre Barreira

Jian-hua He

Wojciech A. Hellwing

Kazuya Koyama

Claudio Llinares

Gong-Bo Zhao



Abstract

We describe and demonstrate the potential of a new and very efficient method for simulating certain classes of modified gravity theories, such as the widely studied f(R) gravity models. High resolution simulations for such models are currently very slow due to the highly nonlinear partial differential equation that needs to be solved exactly to predict the modified gravitational force. This nonlinearity is partly inherent, but is also exacerbated by the specific numerical algorithm used, which employs a variable redefinition to prevent numerical instabilities. The standard Newton-Gauss-Seidel iterative method used to tackle this problem has a poor convergence rate. Our new method not only avoids this, but also allows the discretised equation to be written in a form that is analytically solvable. We show that this new method greatly improves the performance and efficiency of f(R) simulations. For example, a test simulation with 5123 particles in a box of size 512 Mpc/h is now 5 times faster than before, while a Millennium-resolution simulation for f(R) gravity is estimated to be more than 20 times faster than with the old method. Our new implementation will be particularly useful for running very high resolution, large-sized simulations which, to date, are only possible for the standard model, and also makes it feasible to run large numbers of lower resolution simulations for covariance analyses. We hope that the method will bring us to a new era for precision cosmological tests of gravity.

Journal Article Type Article
Acceptance Date Feb 17, 2017
Online Publication Date Feb 28, 2017
Publication Date Feb 28, 2017
Deposit Date Feb 17, 2017
Publicly Available Date Feb 28, 2018
Journal Journal of Cosmology and Astroparticle Physics
Publisher IOP Publishing
Peer Reviewed Peer Reviewed
Volume 2017
Issue 02
Article Number 050
DOI https://doi.org/10.1088/1475-7516/2017/02/050
Public URL https://durham-repository.worktribe.com/output/1365189
Related Public URLs http://adsabs.harvard.edu/abs/2016arXiv161109375B

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Copyright Statement
This is an author-created, un-copyedited version of an article published in Journal of Cosmology and Astroparticle Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1475-7516/2017/02/050






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