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arXiv 2206.04086gr-qcastro-ph.COhep-th
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大质量引力中结构的线性增长

Linear growth of structure in massive gravity

Ekapob Kulchoakrungsun, Ananya Mukherjee, Nishant Agarwal, Anthony R. Pullen

摘要:

本文研究了大质量引力下扩展的准夸克体系中的背景动力学和物质扰动的增长。对于微扰的分析,我们首先选择一个标量场物质分量,得到所有标量微扰稳定的条件。我们在物质场的幺正规范下工作,这使得我们可以直接映射到广义相对论极限下的已知结果。通过进行参数搜索,我们发现,扰动一般是不稳定的,而一个特定的选择的潜在的,其中的标量场有效地表现得像无压物质,允许稳定的扰动。接下来我们考虑在冷暗物质主导的宇宙中物质扰动的增长。在共形牛顿规范下,我们得到了包括增长因子和增长率在内的各种观测量的演化方程,并在准静态和亚视界近似下发现了与尺度无关的增长。最后,我们展示了哈勃参数和物质扰动如何在大质量引力中演变为特定的参数值,以及这种演变与由宇宙学常数和冷暗物质组成的标准宇宙学模型相比如何。

英文摘要:

We study background dynamics and the growth of matter perturbations in the extended quasidilaton setup of massive gravity. For the analysis of perturbations, we first choose a scalar field matter component and obtain the conditions under which all scalar perturbations are stable. We work in unitary gauge for the matter field, which allows us to directly map to known results in the limit of general relativity. By performing a parameter search, we find that the perturbations are unstable in general, while a particular choice of potential, where the scalar field effectively behaves like pressureless matter, allows for stable perturbations. We next consider the growth of matter perturbations in a cold dark matter-dominated Universe. Working in conformal Newtonian gauge, we obtain evolution equations for various observables including the growth factor and growth rate, and find scale-independent growth in the quasistatic and subhorizon approximations. We finally show how the Hubble parameter and matter perturbations evolve in massive gravity for a specific choice of parameter values, and how this evolution compares to the standard cosmological model consisting of a cosmological constant and cold dark matter.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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