论文标题
测试修饰的重力宇宙学的新措施
New measures to test modified gravity cosmologies
论文作者
论文摘要
观察到的宇宙的加速膨胀可以通过黑暗能量或宇宙学量表上的一般相对性（GR）的分解来解释。当后一种情况（即修改的重力方案）被考虑时，通常假定背景进化与$λ$ CDM模型相同，但密度扰动的演变方式不同。在本文中，我们研究了更一般的修饰重力类别，其中背景和扰动演变都与$λ$ CDM模型中的反应偏离。我们介绍了两个相图，$α{\ rm-}fσ_8$和$ h {\ rm-}fσ_8$图表; $ h $是扩展率，$fσ_8$是宇宙增长率和密度波动的归一化的组合，密度波动的正常化直接受到红移空间扭曲的约束，而$α$是一个参数，是一个参数，表征了重力偏离GR的偏差，并且可以通过重力透镜来探测。我们考虑了Horndeski理论的几个特定示例，这是一种一般的标量调整理论，并证明了与$λ$ CDM模型的偏差如何出现在$α{\ rm-}Fσ_8$和$ h {\ rm-}Fσ_8$图中。预测的偏差将对未来的大规模结构观测值有用，以排除某些修饰的重力模型。
The observed accelerated expansion of the Universe may be explained by dark energy or the breakdown of general relativity (GR) on cosmological scales. When the latter case, a modified gravity scenario, is considered, it is often assumed that the background evolution is the same as the $Λ$CDM model but the density perturbation evolves differently. In this paper, we investigate more general classes of modified gravity, where both the background and perturbation evolutions are deviated from those in the $Λ$CDM model. We introduce two phase diagrams, $α{\rm-}fσ_8$ and $H{\rm-}fσ_8$ diagrams; $H$ is the expansion rate, $fσ_8$ is a combination of the growth rate of the Universe and the normalization of the density fluctuation which is directly constrained by redshift-space distortions, and $α$ is a parameter which characterizes the deviation of gravity from GR and can be probed by gravitational lensing. We consider several specific examples of Horndeski's theory, which is a general scalar-tensor theory, and demonstrate how deviations from the $Λ$CDM model appears in the $α{\rm-}fσ_8$ and $H{\rm-}fσ_8$ diagrams. The predicted deviations will be useful for future large-scale structure observations to exclude some of the modified gravity models.
