Anisotropic bispectrum of curvature perturbations from primordial non-Abelian vector fields
Anisotropic bispectrum of curvature perturbations from primordial non-Abelian vector fields
复制标题
原初非阿贝尔矢量场曲率扰动的各向异性双谱
DOI：
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
A. Riotto
中科院分区：
文献类型：
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作者：
N. Bartolo;E. Dimastrogiovanni;S. Matarrese;A. Riotto
在产生曲率扰动的模型中，我们考虑了一个原始SU(2)向量乘子在膨胀过程中的作用。最近，考虑到在宇宙扰动中产生某种程度的统计各向异性的有趣可能性，向量场填充的模型受到了很多关注。我们提出的方案是由以下事实强烈推动的：对于非阿贝尔规范场，自相互作用负责在宇宙学相关函数中产生额外的项，这些项在阿贝尔情况中自然不存在。我们使用N公式和Schwinger-Keldysh公式来计算曲率摄动双谱的这些额外贡献。旋转不变性的原始违反（由于引入了SU(2)规范多重）在相关函数上留下了印记，正如预期的那样，在我们的结果中引入了一定程度的统计各向异性。我们计算了非高斯参数f_{NL}，证明了来自规范玻色子自相互作用的新贡献可能是重要的，在某些情况下是主要的贡献。我们研究了双谱的形状，发现它在局部构型中达到峰值，其振幅由打破统计各向同性的首选方向调制。
We consider a primordial SU(2) vector multiplet during inflation in models where quantum fluctuations of vector fields are involved in producing the curvature perturbation. Recently, a lot of attention has been paid to models populated by vector fields, given the interesting possibility of generating some level of statistical anisotropy in the cosmological perturbations. The scenario we propose is strongly motivated by the fact that, for non-Abelian gauge fields, self-interactions are responsible for generating extra terms in the cosmological correlation functions, which are naturally absent in the Abelian case. We compute these extra contributions to the bispectrum of the curvature perturbation, using the delta N formula and the Schwinger-Keldysh formalism. The primordial violation of rotational invariance (due to the introduction of the SU(2) gauge multiplet) leaves its imprint on the correlation functions introducing, as expected, some degree of statistical anisotropy in our results. We calculate the non-Gaussianity parameter f_{NL}, proving that the new contributions derived from gauge bosons self-interactions can be important, and in some cases the dominat ones. We study the shape of the bispectrum and we find that it turns out to peak in the local configuration, with an amplitude that is modulated by the preferred directions that break statistical isotropy.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.