Primordial tensor non-Gaussianities from general single-field inflation with non-Bunch-Davies initial states
Primordial tensor non-Gaussianities from general single-field inflation with non-Bunch-Davies initial states
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DOI：
10.1103/physrevd.102.023513
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发表时间：
2020-03
影响因子：
5
通讯作者：
Shingo Akama;S. Hirano;Tsutomu Kobayashi
中科院分区：
文献类型：
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作者：
Shingo Akama;S. Hirano;Tsutomu Kobayashi
结果表明，由于亚视界尺度上微扰之间的相互作用，非Bunch-Davies初态的曲率微扰的原始非高斯性比Bunch-Davies初态的曲率微扰的原始非高斯性得到增强.本文的目的是研究张量非高斯性是否也可以通过相同的机制增强。考虑了暴胀子存在下的一般引力理论，计算了一个张量模和两个标量模的张量自双谱和互双谱，其中张量模的初态为非Bunch-Davies态.与标量自双谱的关键区别在于张量三点函数在平坦的动量三角形处消失。我们指出，交叉双谱可以潜在地增强在非平凡的三角形形状，由于非Bunch-Davies初始状态。
It has been found that the primordial non-Gaussianity of the curvature perturbation in the case of non-Bunch-Davies initial states can be enhanced compared with those in the case of the Bunch-Davies one due to the interactions among the perturbations on subhorizon scales. The purpose of the present paper is to investigate whether tensor non-Gaussianities can also be enhanced or not by the same mechanism. We consider general gravity theory in the presence of an inflaton, and evaluate the tensor auto-bispectrum and the cross-bispectrum involving one tensor and two scalar modes with the non-Bunch-Davies initial states for tensor modes. The crucial difference from the case of the scalar auto-bispectrum is that the tensor three-point function vanishes at the flattened momentum triangles. We point out that the cross-bispectrum can potentially be enhanced at non-trivial triangle shapes due to the non-Bunch-Davies initial states.