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Systematic simulations of modified gravity: chameleon models

Brax, P.; Davis, A.-C.; Li, B.; Winther, H.A.; Zhao, G.-B.

Authors

P. Brax

A.-C. Davis

H.A. Winther

G.-B. Zhao



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.

Journal Article Type Article
Publication Date Apr 10, 2013
Deposit Date Mar 27, 2013
Publicly Available Date May 8, 2014
Journal Journal of Cosmology and Astroparticle Physics
Publisher IOP Publishing
Peer Reviewed Peer Reviewed
Volume 2013
Issue 04
Article Number 029
DOI https://doi.org/10.1088/1475-7516/2013/04/029
Keywords Modified gravity, Power spectrum, Cosmological simulations, Particle physics - cosmology connection.
Public URL https://durham-repository.worktribe.com/output/1481358
Publisher URL http://iopscience.iop.org/1475-7516/2013/04/029/

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