Modified gravity<i>N</i>-body code comparison project

Winther, Hans A.; Schmidt, Fabian; Barreira, Alexandre; Arnold, Christian; Bose, Sownak; Llinares, Claudio; Baldi, Marco; Falck, Bridget; Hellwing, Wojciech A.; Koyama, K.; Li, Baojiu; Mota, David F.; Puchwein, Ewald; Smith, R. E.; Zhao, Gong-Bo

doi:10.1093/mnras/stv2253

Cited by 127 publications

(160 citation statements)

References 136 publications

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“…smaller (comparable to the discrepancies in the predictions of different modified gravity simulation codes [46]). The same method, however, does not work as accurately in chameleontype models (see Appendix A), the simulations for which are much more expensive than those for the Vainshtein-type models.…”

Section: Introductionsupporting

confidence: 61%

“…Using the generic parametrisation for modified gravity theories [39,40], ECOSMOG was extended to incorporate chameleon, dilaton and symmetron models [41,42] in general. ECOS-MOG has recently been compared with other codes developed subsequently, including MG-GADGET [43], Isis [44] and MG-ENZO [45] and very good agreement was found between all these codes [46].…”

Section: Introductionmentioning

confidence: 94%

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Speeding upN-body simulations of modified gravity: chameleon screening models

Bose

Barreira

et al. 2017

J. Cosmol. Astropart. Phys.

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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 512 3 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.

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Section: Introductionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 94%

Speeding upN-body simulations of modified gravity: chameleon screening models

Bose

Barreira

et al. 2017

J. Cosmol. Astropart. Phys.

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“…The code that this paper is based on is a slight modification of ISIS ), which in turn is a modification of the RAMSES hydrodynamic N-body code (Teyssier 2002). See also Zhao et al (2011), Li et al (2012a), Oyaizu et al (2008, Mota et al (2008), Boehmer et al (2010), Zumalacarregui et al (2013), Puchwein et al (2013) for other codes that have implemented and performed simulations of f (R) gravity and Winther et al (2015) for a recent code comparison between these codes.…”

Section: Introductionmentioning

confidence: 99%

N-body simulations ofγgravity

Santos

Winther

Mota

et al. 2016

A&A

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We have investigated structure formation in the γ gravity f (R) model with N-body simulations. The γ gravity model is a proposal which, unlike other viable f (R) models, not only changes the gravitational dynamics, but can in principle also have signatures at the background level that are different from those obtained in ΛCDM (Cosmological constant, Cold Dark Matter). The aim of this paper is to study the nonlinear regime of the model in the case where, at late times, the background differs from ΛCDM. We quantify the signatures produced on the power spectrum, the halo mass function, and the density and velocity profiles. To appreciate the features of the model, we have compared it to ΛCDM and the Hu-Sawicki f (R) models. For the considered set of parameters we find that the screening mechanism is ineffective, which gives rise to deviations in the halo mass function that disagree with observations. This does not rule out the model per se, but requires choices of parameters such that | f R0 | is much smaller, which would imply that its cosmic expansion history cannot be distinguished from ΛCDM at the background level.

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“…This non-static solver was already applied to symmetron and disformal gravity models Hagala et al 2016). A comparison between the accuracy of this code and other codes that solve the same set of equations can be found in Winther et al (2015).…”

Section: The N-body Codementioning

confidence: 99%

Probing scalar tensor theories for gravity in redshift space

Sabiu

Mota

Llinares

et al. 2016

A&A

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We present measurements of the spatial clustering statistics in redshift space of various scalar field modified gravity simulations. We utilise the two-point and three-point correlation functions to quantify the spatial distribution of dark matter halos within these simulations and thus discriminate between the models. We compare Λ cold dark matter (ΛCDM) simulations to various modified gravity scenarios and find consistency with previous work in terms of two-point statistics in real and redshift space. However, using higher-order statistics such as the three-point correlation function in redshift space we find significant deviations from ΛCDM hinting that higher-order statistics may prove to be a useful tool in the hunt for deviations from General Relativity.

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Modified gravityN-body code comparison project

Cited by 127 publications

References 136 publications

Speeding upN-body simulations of modified gravity: chameleon screening models

Speeding upN-body simulations of modified gravity: chameleon screening models

N-body simulations ofγgravity

Probing scalar tensor theories for gravity in redshift space

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