Primordial statistical anisotropy generated at the end of inflation
Primordial statistical anisotropy generated at the end of inflation
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DOI：
10.1088/1475-7516/2008/08/005
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发表时间：
2008-05
影响因子：
6.4
通讯作者：
Shuichiro Yokoyama;J. Soda
中科院分区：
文献类型：
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作者：
Shuichiro Yokoyama;J. Soda
我们提出了一种生成曲率扰动的原始统计各向异性的新机制。我们引入了一个向量场，它具有非最小动力学项，并与混合膨胀模型中的瀑布场耦合。在这样的系统中，矢量场给出暴胀结束时的波动，因此引起曲率扰动的子分量。由于向量有一个优选方向，统计各向异性可能会出现在波动中。我们提出了原始功率谱和曲率扰动双谱中统计各向异性的显式公式。有趣的是，统计各向异性有可能没有出现在功率谱中，而是出现在双谱中。我们还发现统计各向异性提供了双谱的形状依赖性。
We present a new mechanism for generating primordial statistical anisotropy of curvature perturbations. We introduce a vector field which has a non-minimal kinetic term and couples with a waterfall field in a hybrid inflation model. In such a system, the vector field gives fluctuations of the end of inflation and hence induces a subcomponent of curvature perturbations. Since the vector has a preferred direction, the statistical anisotropy could appear in the fluctuations. We present the explicit formula for the statistical anisotropy in the primordial power spectrum and the bispectrum of curvature perturbations. Interestingly, there is the possibility that the statistical anisotropy does not appear in the power spectrum but does appear in the bispectrum. We also find that the statistical anisotropy provides the shape dependence to the bispectrum.