Anisotropic dark energy and CMB anomalies
Anisotropic dark energy and CMB anomalies
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各向异性暗能量和 CMB 异常
DOI：
10.1103/physrevd.80.023531
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发表时间：
2009
影响因子：
5
通讯作者：
Battye R
中科院分区：
文献类型：
--
作者：
Battye R
我们研究了由具有点对称性的能量动量张量的暗能量分量引起的全局统计各向同性的破坏，该能量动量张量可以代表立方或六方晶格。在这种高斯模型中，暴胀过程中产生的绝热初始条件可能导致宇宙微波背景的各向异性，其球谐系数是相关的，这与标准假设相反。我们开发了一种视线积分方法，该方法可应用于背景能量动量张量是各向同性的模型，但其线性化扰动是各向异性的。然后我们展示如何将其应用于立方对称和六角对称的情况。我们计算的数量表明，即使在最极端的参数选择下，此类模型也与各向同性模型无法区分，这与基于通货膨胀的各向异性初始条件的模型形成鲜明对比。其原因是基于暗能量的模型通过积分萨克斯-沃尔夫效应对 CMB 各向异性产生影响，这仅在暗能量占主导地位时（即在最大尺度上）才相关。然而，对于暴胀模型来说，各向异性存在于所有尺度上。
We investigate the breaking of global statistical isotropy caused by a dark energy component with an energy-momentum tensor which has point symmetry, that could represent a cubic or hexagonal crystalline lattice. In such models Gaussian, adiabatic initial conditions created during inflation can lead to anisotropies in the cosmic microwave background whose spherical harmonic coefficients are correlated, contrary to the standard assumption. We develop an adaptation of the line of sight integration method that can be applied to models where the background energy-momentum tensor is isotropic, but whose linearized perturbations are anisotropic. We then show how this can be applied to the cases of cubic and hexagonal symmetry. We compute quantities which show that such models are indistinguishable from isotropic models even in the most extreme parameter choices, in stark contrast to models with anisotropic initial conditions based on inflation. The reason for this is that the dark energy based models contribute to the CMB anisotropy via the integrated Sachs-Wolfe effect, which is only relevant when the dark energy is dominant, that is, on the very largest scales. For inflationary models, however, the anisotropy is present on all scales.