Axion-inflation models are a compelling candidate as a mechanism behind the accelerated expansion in the early universe in light of the possibility to embed them in higher dimensional UV complete theories and the exciting prospect of testing them with next-generation cosmological probes. Adding an Abelian gauge sector to axion-inflation models makes for a rich, interesting, phenomenology spanning from primordial black holes to gravitational waves (GWs). Several recent studies employ an approximate analytic (Gaussian) template to characterize the effect of gauge field production on cosmological perturbations. In this work we go beyond such approximation and numerically study particle production and the ensuing scalar and tensor spectra. We find a significant deviation from results based on log-normally distributed vector field excitations. As an important phenomenological application of the improved method, we study the expected chirality and spectral index of the sourced GW background at scales relevant for current and next-generation GW detectors. One striking feature is that of a scale-dependent chirality. We derive a consistency relation between these two observables that can serve as an important tool in identifying key signatures of multi-field dynamics in axion inflation.

中文翻译：

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膨胀过程中尺度依赖性手性作为 Abelian 规范场的冒烟枪


轴子膨胀模型是一个令人信服的候选模型，因为它有可能将其嵌入更高维的 UV 完整理论中，并且具有使用下一代宇宙学探针测试它们的令人兴奋的前景。在轴子膨胀模型中加入阿贝尔规范扇区，可以得到一个丰富、有趣的现象学，从原始黑洞到引力波 （GW）。最近的几项研究采用近似解析（高斯）模板来描述规范场产生对宇宙学扰动的影响。在这项工作中，我们超越了这种近似，对粒子产生以及随之而来的标量和张量光谱进行了数值研究。我们发现与基于对数正态分布矢量场激励的结果存在显著偏差。作为改进方法的重要现象学应用，我们在与当前和下一代 GW 探测器相关的尺度上研究了源 GW 背景的预期手性和光谱指数。一个显着的特征是依赖于尺度的手性。我们推导出了这两个可观察对象之间的一致性关系，可以作为识别轴子膨胀中多场动力学关键特征的重要工具。