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Systematic simulations of modified gravity : chameleon models.

Brax, P. and Davis, A.-C. and Li, B. and Winther, H. A. and Zhao, G.-B. (2013) 'Systematic simulations of modified gravity : chameleon models.', Journal of cosmology and astroparticle physics., 2013 (04). 029.

Abstract

In this work we systematically study the linear and nonlinear structure formation in chameleon theories of modified gravity, using a generic parameterisation which describes a large class of models using only 4 parameters. For this we have modified the N-body simulation code ecosmog to perform a total of 65 simulations for different models and parameter values, including the default ΛCDM. These simulations enable us to explore a significant portion of the parameter space. We have studied the effects of modified gravity on the matter power spectrum and mass function, and found a rich and interesting phenomenology where the difference with the ΛCDM paradigm cannot be reproduced by a linear analysis even on scales as large as k ~ 0.05 hMpc−1, since the latter incorrectly assumes that the modification of gravity depends only on the background matter density. Our results show that the chameleon screening mechanism is significantly more efficient than other mechanisms such as the dilaton and symmetron, especially in high-density regions and at early times, and can serve as a guidance to determine the parts of the chameleon parameter space which are cosmologically interesting and thus merit further studies in the future.

Item Type:Article
Keywords:Modified gravity, Power spectrum, Cosmological simulations, Particle physics - cosmology connection.
Full text:(NA) Not Applicable
Download PDF (arXiv version)
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Status:Peer-reviewed
Publisher Web site:http://iopscience.iop.org/1475-7516/2013/04/029/
Publisher statement:This is an author-created, un-copyedited version of an article accepted for publication 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 http://iopscience.iop.org/1475-7516/2013/04/029/.
Date accepted:No date available
Date deposited:No date available
Date of first online publication:April 2013
Date first made open access:No date available

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