While Efimov physics in ultracold atoms is usually modeled with an isolated Feshbach resonance, many real world resonances appear in close vicinity to each other and are therefore overlapping. Here we derive a realistic model based on the mutual coupling of an open channel and two closed molecular channels while neglecting short-range physics as permitted by the narrow character of the considered resonances. The model is applied to three distinct scenarios with experimental relevance. We show that the effect of overlapping resonances is manifested most strikingly at a narrow resonance in whose vicinity there is a slightly narrower one. In this system the Efimov ground state extends not only over the scattering length zero crossing between the two resonances but also over the pole of the second resonance to finally meet the dissociation threshold below it. In the opposite scenario, when a narrow resonance is considered in the vicinity of a slightly broader one, we observe that the Efimov features are pushed to lower binding energies and smaller scattering lengths by a significant factor facilitating their experimental investigation. Both scenarios are compared with the case of two narrow resonances which are far enough away from each other to be effectively decoupled. In this case the two-channel model results are recovered. Finally, we analyze the rich excitation spectrum of the system and construct and explain its nodal pattern.

中文翻译：

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重叠窄 Feshbach 共振的 Efimov 场景

虽然超冷原子中的 Efimov 物理学通常使用孤立的 Feshbach 共振建模，但许多现实世界的共振出现在彼此附近，因此重叠。在这里，我们基于开放通道和两个封闭分子通道的相互耦合得出了一个现实模型，同时忽略了所考虑共振的窄特征所允许的短程物理。该模型应用于具有实验相关性的三个不同场景。我们表明重叠共振的影响在狭窄的共振中最显着，其附近有一个稍微窄的共振。在这个系统中，Efimov 基态不仅在两个共振之间的散射长度零交叉上延伸，而且在第二个共振的极点上延伸，最终满足低于它的解离阈值。在相反的情况下，当在稍宽的共振附近考虑狭窄的共振时，我们观察到 Efimov 特征被推动到更低的结合能和更小的散射长度，这是一个促进他们实验研究的重要因素。这两种情况都与两个窄共振的情况进行了比较，它们彼此相距足够远，可以有效地解耦。在这种情况下，恢复了双通道模型结果。最后，我们分析了系统丰富的激发谱，构建并解释了其节点模式。当在稍宽的共振附近考虑狭窄的共振时，我们观察到 Efimov 特征被推动到更低的结合能和更小的散射长度，这是一个促进他们实验研究的重要因素。这两种情况都与两个窄共振的情况进行了比较，它们彼此相距足够远，可以有效地解耦。在这种情况下，恢复了双通道模型结果。最后，我们分析了系统丰富的激发谱，构建并解释了其节点模式。当在稍宽的共振附近考虑狭窄的共振时，我们观察到 Efimov 特征被推动到更低的结合能和更小的散射长度，这是一个促进他们实验研究的重要因素。这两种情况都与两个窄共振的情况进行了比较，它们彼此相距足够远，可以有效地解耦。在这种情况下，恢复了双通道模型结果。最后，我们分析了系统丰富的激发谱，构建并解释了其节点模式。这两种情况都与两个窄共振的情况进行了比较，它们彼此相距足够远，可以有效地解耦。在这种情况下，恢复了双通道模型结果。最后，我们分析了系统丰富的激发谱，构建并解释了其节点模式。这两种情况都与两个窄共振的情况进行了比较，它们彼此相距足够远，可以有效地解耦。在这种情况下，双通道模型结果被恢复。最后，我们分析了系统丰富的激发谱，构建并解释了其节点模式。