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arXiv 2302.14530astro-ph.COgr-qchep-phhep-th
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来自超哈勃宇宙学涨落的空间曲率

Spatial Curvature from Super-Hubble Cosmological Fluctuations

Baptiste Blachier, Pierre Auclair, Christophe Ringeval, Vincent Vennin

AI总结:

本文研究超哈勃涨落如何诱导随机空间曲率,推导曲率密度参数的非微扰统计分布,发现当今最概然值约为-10⁻⁹、均值约+10⁻⁹,且长时间暴胀可产生可观曲率。

摘要:

我们重新审视了超哈勃宇宙学涨落在宇宙历史任意时刻如何诱导局部背景度规产生非零空间曲率。这些涨落的随机性质使曲率密度参数成为一个随机量,我们为其推导了新的非微扰表达式,涵盖其均值、方差、高阶矩以及完整概率分布。对于尺度不变的高斯扰动(例如宇宙学观测所偏好的那种),我们发现今天曲率密度参数 $Ω_\mathrm{K}$ 的最概然值为 $-10^{-9}$,其均值为 $+10^{-9}$,两者都被量级为 $10^{-5}$ 的标准差所淹没。随后我们讨论了这些数值会如何受到大尺度超哈勃非高斯性的影响,或者如果暴胀持续了极长时间又会如何。特别地,我们发现如果暴胀持续超过十亿个e-fold,就能得到可观的 $Ω_\mathrm{K}$ 值。

英文摘要:

We revisit how super-Hubble cosmological fluctuations induce, at any time in the cosmic history, a non-vanishing spatial curvature of the local background metric. The random nature of these fluctuations promotes the curvature density parameter to a stochastic quantity for which we derive novel non-perturbative expressions for its mean, variance, higher moments and full probability distribution. For scale-invariant Gaussian perturbations, such as those favored by cosmological observations, we find that the most probable value for the curvature density parameter $Ω_\mathrm{K}$ today is $-10^{-9}$, that its mean is $+10^{-9}$, both being overwhelmed by a standard deviation of order $10^{-5}$. We then discuss how these numbers would be affected by the presence of large super-Hubble non-Gaussianities, or, if inflation lasted for a very long time. In particular, we find that substantial values of $Ω_\mathrm{K}$ are obtained if inflation lasts for more than a billion e-folds.

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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