f (R) gravity on non-linear scales: the post-Friedmann expansion and the vector potential

	f (R) gravity on non-linear scales: the post-Friedmann expansion and the vector potential
	Thomas, D. B.1,2; Bruni, M.2; Koyama, K.2; Li, B.3; Zhao, G. -B.2,4
刊名	JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
	2015-07-01
期号	7
关键词	modified gravity cosmological simulations
英文摘要	Many modified gravity theories are under consideration in cosmology as the source of the accelerated expansion of the universe and linear perturbation theory, valid on the largest scales, has been examined in many of these models. However, smaller non-linear scales offer a richer phenomenology with which to constrain modified gravity theories. Here, we consider the Hu-Sawicki form of f(R) gravity and apply the post-Friedmann approach to derive the leading order equations for non-linear scales, i.e. the equations valid in the Newtonian-like regime. We reproduce the standard equations for the scalar field, gravitational slip and the modified Poisson equation in a coherent framework. In addition, we derive the equation for the leading order correction to the Newtonian regime, the vector potential. We measure this vector potential from f(R) N-body simulations at redshift zero and one, for two values of the fRo parameter. We find that the vector potential at redshift zero in f (R) gravity can be close to 50% larger than in GR on small scales for vertical bar integral R-0 vertical bar= 1.289 x 10(-5), although this is less for larger scales, earlier times and smaller values of the fRo parameter. Similarly to in GR, the small amplitude of this vector potential suggests that the Newtonian approximation is highly accurate for f (R) gravity, and also that the non-linear cosmological behaviour of f(R) gravity can be completely described by just the scalar potentials and the f (R) field.
收录类别	SCI
语种	英语
WOS记录号	WOS:000359259500051
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/5627]
专题	国家天文台_星系宇宙学研究部
作者单位	1.Univ Cyprus, Dept Phys, CY-2109 Nicosia, Cyprus 2.Univ Portsmouth, Inst Cosmol & Gravitat, Portsmouth PO1 3FX, Hants, England 3.Univ Durham, Dept Phys, Inst Computat Cosmol, Durham DH1 3LE, England 4.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
推荐引用方式 GB/T 7714	Thomas, D. B.,Bruni, M.,Koyama, K.,et al. f (R) gravity on non-linear scales: the post-Friedmann expansion and the vector potential[J]. JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS,2015(7).
APA	Thomas, D. B.,Bruni, M.,Koyama, K.,Li, B.,&Zhao, G. -B..(2015).f (R) gravity on non-linear scales: the post-Friedmann expansion and the vector potential.JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS(7).
MLA	Thomas, D. B.,et al."f (R) gravity on non-linear scales: the post-Friedmann expansion and the vector potential".JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS .7(2015).