Cosmological perturbations in f(T) gravity
Cosmological perturbations in f(T) gravity
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DOI：
10.1103/physrevd.83.023508
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发表时间：
2011-01-10
影响因子：
5
通讯作者：
Saridakis, Emmanuel N.
中科院分区：
文献类型：
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作者：
Chen, Shih-Hung;Dent, James B.;Saridakis, Emmanuel N.
我们研究 f(T) 引力中的宇宙扰动。使用对角 vierbein 检查标量扇区中的纯重力扰动，我们提取相应的色散关系，该关系为 f(T) Ansatze 提供了约束，从而产生了无不稳定的理论。此外，在包含物质扰动后，我们推导了完全扰动的运动方程，并研究了物质超密度的增长。我们表明，f(T) 常数的 f(T) 引力与广义相对论一致，无论是在背景还是一阶扰动水平上。将我们的形式主义应用于幂律模型，我们发现在大次视界尺度（O(100 Mpc) 或更大）上，物质超密度的演化将不同于 Lambda CDM 宇宙学。最后，检查矢量和张量扇区的线性扰动，我们发现（对于 vierbein 的标准选择）f(T) 引力不受大质量引力子的影响。
We investigate the cosmological perturbations in f(T) gravity. Examining the pure gravitational perturbations in the scalar sector using a diagonal vierbein, we extract the corresponding dispersion relation, which provides a constraint on the f(T) Ansatze that lead to a theory free of instabilities. Additionally, upon inclusion of the matter perturbations, we derive the fully perturbed equations of motion, and we study the growth of matter overdensities. We show that f(T) gravity with f(T) constant coincides with General Relativity, both at the background as well as at the first-order perturbation level. Applying our formalism to the power-law model we find that on large subhorizon scales (O(100 Mpc) or larger), the evolution of matter overdensity will differ from Lambda CDM cosmology. Finally, examining the linear perturbations of the vector and tensor sectors, we find that (for the standard choice of vierbein) f(T) gravity is free of massive gravitons.