Modified-source gravity and cosmological structure formation
Modified-source gravity and cosmological structure formation
复制标题
修改源引力和宇宙结构形成
DOI：
10.1088/1367-2630/8/12/323
复制
发表时间：
2006
影响因子：
3.3
通讯作者：
M. Trodden
中科院分区：
文献类型：
--
作者：
S. Carroll;I. Sawicki;A. Silvestri;M. Trodden
解释宇宙加速的一种方法是修改广义相对论，而不是引入暗能量。通常，这样的修改引入新的自由度。考虑没有新自由度的模型是很有趣的，但对传统的能量-动量张量有一个修改的依赖; f（R）理论的Palatini公式就是一个例子。这些理论为宇宙学修正引力的研究提供了一个有趣的试验场。在本文中，我们研究这些“修正源引力”（MSG）理论的结构演化。在线性区域中，密度扰动在后期表现出尺度依赖的失控增长，特别是，给定波数的模式在比标准ΛCDM模型更高的红移处变得非线性。我们讨论了这种行为的影响，为什么有理由预期，增长将被切断的非线性制度。假设这在完全非线性分析中成立，我们简要描述即将到来的测量如何探测修改后的理论和标准ΛCDM模型之间的差异。
One way to account for the acceleration of the universe is to modify general relativity, rather than introducing dark energy. Typically, such modifications introduce new degrees of freedom. It is interesting to consider models with no new degrees of freedom, but with a modified dependence on the conventional energy-momentum tensor; the Palatini formulation of f(R) theories is one example. Such theories offer an interesting testing ground for investigations of cosmological modified gravity. In this paper we study the evolution of structure in these ‘modified-source gravity’ (MSG) theories. In the linear regime, density perturbations exhibit scale dependent runaway growth at late times and, in particular, a mode of a given wavenumber goes nonlinear at a higher redshift than in the standard lambda-cold dark matter (ΛCDM) model. We discuss the implications of this behaviour and why there are reasons to expect that the growth will be cut off in the nonlinear regime. Assuming that this holds in a full nonlinear analysis, we briefly describe how upcoming measurements may probe the differences between the modified theory and the standard ΛCDM model.