标题： 手征引力波的有效场论 显示英文标题

标题： Effective Field Theory of Chiral Gravitational Waves

摘要： 当（非）阿贝尔规范场在暴胀期间获得各向同性的背景构型时，除了固有的无偏振引力波外，还可以产生具有宇称破缺极化的强引力波（称为手征引力波）。然而，以往的研究主要分析了具体的模型，使得这一现象的普适性尚不清楚。为了进行模型无关的分析，我们通过扩展暴胀的有效场论（EFT）并引入规范场，构建了手征引力波的有效场论（EFT）。所得的作用量统一了具有 $SU(2)$ 规范场的暴胀模型（如色自然暴胀和规范暴胀）以及具有三重 $U(1)$ 规范场的模型，系统地涵盖了所有与规范场背景引起的对称性破缺相一致的引力波产生机制。我们发现，在背景规范场的有效能量密度为正且规范动能函数未被精细调整到特定时间依赖的情况下，手征引力波通常不可避免地会产生。这一 EFT 为未来的手征引力波现象学研究以及深化我们对手征引力波理论理解提供了有用的框架。 显示英文摘要

摘要： When a (non-)Abelian gauge field acquires an isotropic background configuration during inflation, strong gravitational waves (GWs) with parity-violating polarization, known as chiral GWs, can be produced in addition to the intrinsic unpolarized GWs. However, previous studies have analyzed individual models, leaving the generality of this phenomenon unclear. To perform a model-independent analysis, we construct an effective field theory (EFT) of chiral GWs by extending the EFT of inflation and incorporating gauge fields. The resulting action unifies inflationary models with a $SU(2)$ gauge field, such as chromo-natural inflation and gauge-flation, and ones with a triplet of $U(1)$ gauge fields, systematically encompassing all possible GW production mechanisms consistent with the symmetry breaking induced by the gauge field background. We find that chiral GWs are generically and inevitably produced, provided that the effective energy density of the background gauge field is positive and the gauge kinetic function is not fine-tuned to a specific time dependence. This EFT offers a useful foundation for future phenomenological studies as well as for deepening our theoretical understanding of chiral GWs.