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An investigation into the dark energy associated with cosmological initial conditions through observations on CMB and the large-scale structure of the universe

通过对宇宙微波背景和宇宙大尺度结构的观测，研究与宇宙学初始条件相关的暗能量

基本信息

批准号：
20J13640
负责人：
南岳
金额：
$ 1.34万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for JSPS Fellows
财政年份：
2020
资助国家：
日本
起止时间：
2020-04-24 至 2022-03-31
项目状态：
已结题

项目摘要

Dark energy is generally considered as a repulsive homogeneous background driving the accelerated expansion in the standard ΛCDM cosmology following the cosmological principle that assumes homogeneity and isotropy on the largest scales. In addition to tensions and anomalies in observations challenging the ΛCDM model, increasing observations indicate the possible breakdown of the cosmological principle.Dark energy is a mystery to be illuminated in the future decades, whose nature may reveal the fate of our Universe, and the secrets of new physics beyond the standard models of cosmology and particle physics. It will be ground-breaking if dark energy inhomogeneities are found in future observations.This research focuses on a general formulation of possible dark energy inhomogeneities as a modification to the standard perturbation theory as a forecasting effort, a step forward from the long-lasting consideration of dynamical dark energy models. Sourced by some ultralight scalar field, dark energy carries isocurvature-type superhorizon fluctuations. These fluctuations translate into inhomogeneous dark energy clustering and consequently anisotropies in cosmological observables within the horizon. Using constraints on these fluctuations from the initial conditions of the cosmic microwave background, the research formulated and discussed the impacts of dark energy clustering on observables such as dark energy equation of state, luminosity distance and matter spectrum of the large-scale structure, which are worth testing by future surveys like Subaru PFS, DESI, LSST, etc.

暗能量通常被认为是在标准ΛCDM宇宙学中驱动加速膨胀的排斥性均匀背景，遵循在最大尺度上假设均匀性和各向同性的宇宙学原理。除了对ΛCDM模型提出挑战的观测中的紧张和异常之外，越来越多的观测表明宇宙学原理可能会崩溃。暗能量是一个在未来几十年将被揭示的谜，它的性质可能会揭示我们宇宙的命运，以及超越宇宙学和粒子物理学标准模型的新物理学的秘密。如果在未来的观测中发现暗能量的不均匀性，这将是突破性的。这项研究的重点是一个可能的暗能量不均匀性的一般公式，作为对标准微扰理论的修正，作为一种预测努力，从长期考虑动态暗能量模型向前迈进了一步。暗能量来源于某些超轻标量场，带有等曲率型超视界波动。这些波动转化为不均匀的暗能量聚集，从而在视界内的宇宙学观测中呈现各向异性。利用宇宙微波背景初始条件对这些波动的约束，研究阐述并讨论了暗能量聚类对大尺度结构暗能量状态方程、光度距离和物质谱等观测值的影响，值得未来的Subaru PFS、DESI、LSST等巡天进行验证。