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Nonlinear structure formation with the environmentally dependent dilaton (2011)
Journal Article
Brax, P., van de Bruck, C., Davis, A., Li, B., & Shaw, D. (2011). Nonlinear structure formation with the environmentally dependent dilaton. Physical Review D, 83, Article 104026. https://doi.org/10.1103/physrevd.83.104026

We have studied the nonlinear structure formation of the environmentally dependent dilaton model using N-body simulations. We find that the mechanism of suppressing the scalar fifth force in high-density regions works very well. Within the parameter... Read More about Nonlinear structure formation with the environmentally dependent dilaton.

Large-scale structure in f(T) gravity (2011)
Journal Article
Li, B., Sotiriou, T., & Barrow, J. (2011). Large-scale structure in f(T) gravity. Physical Review D, 83, Article 104017. https://doi.org/10.1103/physrevd.83.104017

In this work we study the cosmology of the general f(T) gravity theory. We express the modified Einstein equations using covariant quantities, and derive the gauge-invariant perturbation equations in covariant form. We consider a specific choice of f... Read More about Large-scale structure in f(T) gravity.

On the effects of coupled scalar fields on structure formation (2011)
Journal Article
Li, B., & Barrow, J. (2011). On the effects of coupled scalar fields on structure formation. Monthly Notices of the Royal Astronomical Society, 413(1), 262-270. https://doi.org/10.1111/j.1365-2966.2010.18130.x

A coupling between a scalar field (representing the dark energy) and dark matter could produce rich phenomena in cosmology. It affects cosmic structure formation mainly through the fifth force, a velocity-dependent force that acts parallel to particl... Read More about On the effects of coupled scalar fields on structure formation.

f(T) Gravity and local Lorentz invariance (2011)
Journal Article
Li, B., Sotiriou, T., & Barrow, J. (2011). f(T) Gravity and local Lorentz invariance. Physical Review D, 83(6), Article 064035. https://doi.org/10.1103/physrevd.83.064035

We show that in theories of generalized teleparallel gravity, whose Lagrangians are algebraic functions of the usual teleparallel Lagrangian, the action and the field equations are not invariant under local Lorentz transformations. We also argue that... Read More about f(T) Gravity and local Lorentz invariance.

Voids in coupled scalar field cosmology (2011)
Journal Article
Li, B. (2011). Voids in coupled scalar field cosmology. Monthly Notices of the Royal Astronomical Society, 411(4), 2615-2627. https://doi.org/10.1111/j.1365-2966.2010.17867.x

We study the properties of voids in two different types of coupled scalar field theories. Due to the fifth force produced by the scalar field coupling, the matter particles feel stronger attraction amongst each other and cluster more quickly than the... Read More about Voids in coupled scalar field cosmology.

Varying alpha from N-body simulations (2011)
Journal Article
Li, B., Mota, D., & Barrow, J. (2011). Varying alpha from N-body simulations. Astrophysical Journal, 728(2), Article 108. https://doi.org/10.1088/0004-637x/728/2/108

We have studied the Bekenstein-Sandvik-Barrow-Magueijo (BSBM) model for the spatial and temporal variations of the fine structure constant, α, with the aid of full N-body simulations that explicitly and self-consistently solve for the scalar field dr... Read More about Varying alpha from N-body simulations.

N-body simulations for extended quintessence models (2011)
Journal Article
Li, B., Mota, D., & Barrow, J. (2011). N-body simulations for extended quintessence models. Astrophysical Journal, 728(2), Article 109. https://doi.org/10.1088/0004-637x/728/2/109

We introduce the N-body simulation technique to follow structure formation in linear and nonlinear regimes for the extended quintessence models (scalar-tensor theories in which the scalar field has a self-interaction potential and behaves as dark ene... Read More about N-body simulations for extended quintessence models.

N-body simulations for f(R) gravity using a self-adaptive particle-mesh code (2011)
Journal Article
Zhao, G., Li, B., & Koyama, K. (2011). N-body simulations for f(R) gravity using a self-adaptive particle-mesh code. Physical Review D, 83(4), Article 044007. https://doi.org/10.1103/physrevd.83.044007

We perform high-resolution N-body simulations for f(R) gravity based on a self-adaptive particle-mesh code MLAPM. The chameleon mechanism that recovers general relativity on small scales is fully taken into account by self-consistently solving the no... Read More about N-body simulations for f(R) gravity using a self-adaptive particle-mesh code.

N-body simulations for coupled scalar field cosmology (2011)
Journal Article
Li, B., & Barrow, J. (2011). N-body simulations for coupled scalar field cosmology. Physical Review D, 83(2), Article 024007. https://doi.org/10.1103/physrevd.83.024007

We describe in detail the general methodology and numerical implementation of consistent N-body simulations for coupled-scalar-field models, including background cosmology and the generation of initial conditions (with the different couplings to diff... Read More about N-body simulations for coupled scalar field cosmology.

Modified Kepler's law, escape speed and two-body problem in MOND-like theories (2010)
Journal Article
Zhao, H., Li, B., & Bienaymé, O. (2010). Modified Kepler's law, escape speed and two-body problem in MOND-like theories. Physical Review D, 82(10), Article 103001. https://doi.org/10.1103/physrevd.82.103001

We derive a simple analytical expression for the two-body force in a subclass of modified Newtonian dynamics (MOND) theories and make testable predictions in the modification to the two-body orbital period, shape, precession rate, escape speed, etc.... Read More about Modified Kepler's law, escape speed and two-body problem in MOND-like theories.

Structure formation by the fifth force: segregation of baryons and dark matter (2010)
Journal Article
Li, B., & Zhao, H. (2010). Structure formation by the fifth force: segregation of baryons and dark matter. Physical Review D, 81(10), Article 104047. https://doi.org/10.1103/physrevd.81.104047

In this paper we present the results of N-body simulations with a scalar field coupled differently to cold dark matter (CDM) and baryons. The scalar field potential and coupling function are chosen such that the scalar field acquires a heavy mass in... Read More about Structure formation by the fifth force: segregation of baryons and dark matter.

Structure formation by fifth force: power spectrum from N-Body simulations (2010)
Journal Article
Zhao, H., Maccio, A., Li, B., Hoekstra, H., & Feix, M. (2010). Structure formation by fifth force: power spectrum from N-Body simulations. Astrophysical Journal Letters, 712(2), L179-L183. https://doi.org/10.1088/2041-8205/712/2/l179

We lay out the framework to numerically study nonlinear structure formation in the context of scalar-field-coupled cold dark matter models (phivCDM models) where the scalar field phiv serves as dynamical dark energy. Adopting parameters for the scala... Read More about Structure formation by fifth force: power spectrum from N-Body simulations.

Dark fluid: A unified framework for modified Newtonian dynamics, dark matter, and dark energy (2010)
Journal Article
Zhao, H., & Li, B. (2010). Dark fluid: A unified framework for modified Newtonian dynamics, dark matter, and dark energy. Astrophysical Journal, 712(1), 130-141. https://doi.org/10.1088/0004-637x/712/1/130

Empirical theories of dark matter (DM) like modified Newtonian dynamics (MOND) gravity and of dark energy (DE) like f(R) gravity were motivated by astronomical data. But could these theories be branches rooted from a more general and hence generic fr... Read More about Dark fluid: A unified framework for modified Newtonian dynamics, dark matter, and dark energy.

Indistinguishable macroscopic behaviour of Palatini gravities and general relativity (2009)
Journal Article
Li, B., Mota, D., & Shaw, D. (2009). Indistinguishable macroscopic behaviour of Palatini gravities and general relativity. Classical and Quantum Gravity, 26(5), https://doi.org/10.1088/0264-9381/26/5/055018

We show that, within some modified gravity theories, such as the Palatini models, the nonlinear nature of the field equations implies that the usual naïve averaging procedure (replacing the microscopic energy–momentum by its cosmological average) cou... Read More about Indistinguishable macroscopic behaviour of Palatini gravities and general relativity.