Large-scale structure with superhorizon isocurvature dark energy
Large-scale structure with superhorizon isocurvature dark energy
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DOI：
10.1103/physrevd.105.083531
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发表时间：
2021-12
期刊：
影响因子：
4.6
通讯作者：
Koki Yamashita;Yue Nan;Y. Sugiyama;Kazuhiro Yamamoto
中科院分区：
文献类型：
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作者：
Koki Yamashita;Yue Nan;Y. Sugiyama;Kazuhiro Yamamoto
标准的宇宙学模型假设一个均匀各向同性的宇宙作为大尺度的背景时空，称为宇宙学原理。然而，一些观测表明，大尺度上可能存在一个不均匀和各向异性的宇宙。本文在Nan等人的超曲率暗能量模型的基础上，研究了一个具有随机非均匀和各向异性的大尺度宇宙模型。[物理。修订本D 99,103512(2019年)]。在这个模型中，作者引入了一个在比当前视界尺度(超视界尺度)足够大的尺度上具有数学上的{O}(1)$不均匀性的标量场，标量场的势能解释了加速膨胀，但与宇宙学原理略有偏离。我们旨在阐明该模型中物质组分的大尺度结构(LSS)的理论预测。基于Nan和Yamamoto[Phys.]中关于超视界尺度波动(超视界模式)的工作。Rev.D105,063518(2022年)，我们导出了宇宙微扰理论中的微扰分量所服从的方程，解决了暗能量不均匀对宇宙微扰理论的影响。最后，我们通过比较模式数值解预测的$\sigma_8$与Planck和SDSS等观测结果的$\sigma_8$，表明该模式与观测结果是一致的。
The standard cosmological model assumes a homogeneous and isotropic universe as the background spacetime on large scales called the cosmological principle. However, some observations suggest the possibility of an inhomogeneous and anisotropic universe at large scales. In this paper, we investigate a model of the universe with random inhomogeneities and anisotropies on very large scales, motivated by the supercurvature dark energy model in Nan et al. [Phys. Rev. D 99, 103512 (2019)]. In this model, the authors introduced a scalar field with $\mathcal{O}(1)$ inhomogeneities on a scale sufficiently larger than the current horizon scale (superhorizon scale), and the potential energy of the scalar field explains the accelerating expansion, with slight deviations from the cosmological principle. We aim at clarifying the theoretical prediction on the large-scale structure (LSS) of the matter component in this model. Based on the work on the superhorizon scale fluctuations (superhorizon mode) presented in Nan and Yamamoto [Phys. Rev. D 105, 063518 (2022)], we derive the equations that the perturbative components to the LSS obey as a generalization of the cosmological perturbations theory, which is solved to find the influence of the dark energy inhomogeneities on the formation of the LSS. Finally, we show that the model can be consistent with observations by comparing the $\sigma_8$ predicted by the numerical solution of the model with the $\sigma_8$ indicated by observations such as Planck and SDSS.