Spatial curvature at the sound horizon
Spatial curvature at the sound horizon
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DOI：
10.1088/1475-7516/2020/02/034
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发表时间：
2019-11
影响因子：
6.4
通讯作者：
G. Avis;Sadra Jazayeri;E. Pajer;Jakub Supeł
中科院分区：
文献类型：
--
作者：
G. Avis;Sadra Jazayeri;E. Pajer;Jakub Supeł
空间曲率对原始扰动的影响由ΩK，0/cs 2控制，其中ΩK，0是今天的空间曲率分数密度，cs是暴胀时的声速。在这里，我们研究这些影响的限制cs 1。首先，我们证明了平坦宇宙中的标准宇宙学软定理在弯曲宇宙中被违反，并且即使在单钟暴胀中，膨胀子的软极限也可能具有非普适性贡献。这是一个事实的后果，即在空间曲率的存在下，有一个差距之间的频谱剩余的非同态和物理模式。第二，有曲率修正的原始缩放，这不是规模不变的。我们提供了明确的公式，这些修正的功率谱和双谱的曲率在单时钟通货膨胀的线性顺序。我们表明，大尺度CMB各向异性可以提供有趣的新的约束这些曲率效应，因此对ΩK，0/cs 2，但它是必要的，超越我们的线性阶处理。
The effect of spatial curvature on primordial perturbations is controlled by ΩK,0/cs2 , where ΩK,0 is today's fractional density of spatial curvature and cs is the speed of sound during inflation. Here we study these effects in the limit cs≪ 1 . First, we show that the standard cosmological soft theorems in flat universes are violated in curved universes and the soft limits of correlators can have non-universal contributions even in single-clock inflation. This is a consequence of the fact that, in the presence of spatial curvature, there is a gap between the spectrum of residual diffeomorphisms and that of physical modes. Second, there are curvature corrections to primordial correlators, which are not scale invariant. We provide explicit formulae for these corrections to the power spectrum and the bispectrum to linear order in curvature in single-clock inflation. We show that the large-scale CMB anisotropies could provide interesting new constraints on these curvature effects, and therefore on ΩK,0/cs2 , but it is necessary to go beyond our linear-order treatment.