The two-field regime of natural inflation
The two-field regime of natural inflation
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DOI：
10.1088/1475-7516/2015/12/044
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发表时间：
2015-10
影响因子：
6.4
通讯作者：
A. Ach'ucarro;Vicente Atal;M. Kawasaki;F. Takahashi
中科院分区：
文献类型：
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作者：
A. Ach'ucarro;Vicente Atal;M. Kawasaki;F. Takahashi
自然暴胀最简单的双场完备化存在这样一种机制：两个场都处于活跃状态，且其预测结果在普朗克1 - σ置信区间内。我们针对自然暴胀的原始模型展示了这一点，在该模型中，暴胀是通过明确破缺U(1)对称性来实现的。我们考虑这样一种情况：由这种对称性明确破缺产生的质量与自发破缺产生的质量相当，我们证明这与相应能量尺度之间的层级关系是一致的。当可观测模式离开视界时，两个质量相当，但在暴胀的最后几个e - 折叠阶段，质量层级得以恢复，这使得预测结果与等曲率限制条件相符。为完整起见，我们还研究了质量存在较大层级且存在由（重）径向场驱动的初始暴胀阶段这种情况下的预测结果。
The simplest two-field completion of natural inflation has a regime in which both fields are active and in which its predictions are within the Planck 1-σ confidence contour. We show this for the original model of natural inflation, in which inflation is achieved through the explicit breaking of a U(1) symmetry. We consider the case in which the mass coming from explicit breaking of this symmetry is comparable to that from spontaneous breaking, which we show is consistent with a hierarchy between the corresponding energy scales. While both masses are comparable when the observable modes left the horizon, the mass hierarchy is restored in the last e-foldings of inflation, rendering the predictions consistent with the isocurvature bounds. For completeness, we also study the predictions for the case in which there is a large hierarchy of masses and an initial period of inflation driven by the (heavy) radial field.