The key to the phenomenological success of inflation models with axion and SU(2) gauge fields is the isotropic background of the SU(2) field. Previous studies showed that this isotropic background is an attractor solution during inflation starting from anisotropic (Bianchi Type I) spacetime; however, not all possible initial anisotropic parameter space was explored. In this paper, we explore more generic initial conditions without assuming the initial slow-roll dynamics. We find some initial anisotropic parameter space which does not lead to the isotropic background, but to violation of slow-roll conditions, terminating inflation prematurely. The basin of attraction increases when we introduce another scalar field acting as inflaton and make the axion-SU(2) system a spectator sector. Therefore, the spectator axion-SU(2) model is phenomenologically more attractive.

中文翻译：

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axion-SU(2) 膨胀的各向同性吸引子解的吸引力如何？

具有轴子和 SU(2) 规范场的暴胀模型在现象学上取得成功的关键是 SU(2) 场的各向同性背景。先前的研究表明，这种各向同性背景是从各向异性（Bianchi Type I）时空开始的暴胀过程中的一个吸引子解；然而，并未探索所有可能的初始各向异性参数空间。在本文中，我们在不假设初始慢滚动力学的情况下探索了更通用的初始条件。我们发现一些初始各向异性参数空间不会导致各向同性背景，但会违反慢滚条件，过早终止膨胀。当我们引入另一个作为暴胀子的标量场并使 axion-SU(2) 系统成为旁观者部门时，吸引力盆地会增加。所以，