We develop a possibility of generating tensor non-Gaussianity in a kind of anisotropic inflation, where a (1) gauge field is kinetically coupled to a spectator scalar field. Owing to this coupling, the coherent mode of the electric field appears and softly breaks the isotropy of the Universe. We compute the bispectrum of linearly-polarized tensor perturbations sourced by the gauge field and find that it is strongly red-tilted and has distinctive statistical anisotropies including higher-order multipole moments. Interestingly, the tensor bispectra with the specific combinations of linear polarization modes are dominant, and their amplitudes depend on the different sets of multipole moments. This new type of statistically-anisotropic tensor non-Gaussianity can be potentially testable with the upcoming cosmic microwave background B-mode polarizationexperiments.

我们开发了一种在一种各向异性膨胀中产生张量非高斯性的可能性，其中（1）规范场与旁观者标量场动力学耦合。由于这种耦合，电场的相干模式出现并轻轻打破了宇宙的各向同性。我们计算了由规范场产生的线性极化张量扰动的双谱，发现它具有强烈的红色倾斜，并具有独特的统计各向异性，包括高阶多极矩。有趣的是，具有特定线性偏振模式组合的张量双谱占主导地位，它们的幅度取决于不同的多极矩集。