Emergence of Chaotic Scattering in Ultracold Er and Dy
Emergence of Chaotic Scattering in Ultracold Er and Dy
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DOI：
10.1103/physrevx.5.041029
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发表时间：
2015-11-19
影响因子：
12.5
通讯作者：
Kotochigova, S.
中科院分区：
文献类型：
--
作者：
Maier, T.;Kadau, H.;Kotochigova, S.
我们发现，超冷磁性镧系原子的混沌散射出现由于各向异性的相互作用势和塞曼耦合下的外部磁场。这种散射研究在一个合作的实验和理论的努力，镝和铒。我们提出了广泛的原子损失测量其密集的磁Feshbach共振光谱，分析其统计特性，并比较从随机矩阵理论启发的模型预测。此外，理论耦合通道模拟的各向异性分子哈密顿量在零磁场表明，弱约束，近阈值双原子水平形成重叠，非耦合混沌序列时，结合随机分布。塞曼相互作用的位移和耦合这些水平，导致Feshbach光谱的零能量束缚态与最近邻间距的变化，从随机到混乱分布的磁场增加。最后，我们表明，一个小的，但相当大的分数的共振在Dy和Er原子损失谱的极端温度敏感性是由于共振非零分波碰撞。我们对这些共振的阈值分析表明，三体复合率的碰撞能量依赖性很大。
We show that for ultracold magnetic lanthanide atoms chaotic scattering emerges due to a combination of anisotropic interaction potentials and Zeeman coupling under an external magnetic field. This scattering is studied in a collaborative experimental and theoretical effort for both dysprosium and erbium. We present extensive atom-loss measurements of their dense magnetic Feshbach-resonance spectra, analyze their statistical properties, and compare to predictions from a random-matrix-theory-inspired model. Furthermore, theoretical coupled-channels simulations of the anisotropic molecular Hamiltonian at zero magnetic field show that weakly bound, near threshold diatomic levels form overlapping, uncoupled chaotic series that when combined are randomly distributed. The Zeeman interaction shifts and couples these levels, leading to a Feshbach spectrum of zero-energy bound states with nearest-neighbor spacings that changes from randomly to chaotically distributed for increasing magnetic field. Finally, we show that the extreme temperature sensitivity of a small, but sizable fraction of the resonances in the Dy and Er atom-loss spectra is due to resonant nonzero partial-wave collisions. Our threshold analysis for these resonances indicates a large collision-energy dependence of the three-body recombination rate.