The Nature of Primordial Fluctuations from Anisotropic Inflation
The Nature of Primordial Fluctuations from Anisotropic Inflation
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DOI：
10.1143/ptp.123.1041
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发表时间：
2010-02
影响因子：
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通讯作者：
Masa-aki Watanabe;S. Kanno;J. Soda
中科院分区：
文献类型：
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作者：
Masa-aki Watanabe;S. Kanno;J. Soda
本文研究了各向异性暴胀中原初涨落的统计性质，暴胀是由与暴胀子耦合的矢量场实现的。通过推广各向同性暴胀中的平切片规范，我们找到了一个适合于各向异性暴胀的规范，我们称之为正则规范。利用正则规范，我们揭示了曲率微扰，矢量波和引力波之间的耦合结构。我们确定了两个来源的各向异性，即各向异性由于宇宙的各向异性膨胀和由于各向异性变量之间的耦合。事实证明，后一种效应占主导地位。由于曲率扰动与矢量波之间的耦合最强，曲率扰动的统计各向异性比引力波的统计各向异性大。我们发现曲率扰动和引力波之间存在着传统暴胀理论中从未出现过的交叉关联。我们还发现了引力波的线性偏振。最后，我们讨论了我们的结果的宇宙学含义。
We study the statistical nature of primordial fluctuations from an anisotropic inflation which is realized by a vector field coupled to an inflaton. We find a suitable gauge, which we call the canonical gauge, for anisotropic inflation by generalizing the flat slicing gauge in conventional isotropic inflation. Using the canonical gauge, we reveal the structure of the couplings between curvature perturbations, vector waves, and gravitational waves. We identify two sources of anisotropy, i.e. the anisotropy due to the anisotropic expansion of the universe and that due to the anisotropic couplings among variables. It turns out that the latter effect is dominant. Since the coupling between the curvature perturbations and vector waves is the strongest one, the statistical anisotropy in the curvature perturbations is larger than that in gravitational waves. We find the cross correlation between the curvature perturbations and gravitational waves which never occurs in conventional inflation. We also find the linear polarization of gravitational waves. Finally, we discuss cosmological implication of our results.