Adiabatic association of ultracold molecules via magnetic-field tunable interactions
Adiabatic association of ultracold molecules via magnetic-field tunable interactions
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DOI：
10.1088/0953-4075/37/17/006
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发表时间：
2003-12
期刊：
影响因子：
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通讯作者：
K. Góral;T. Koehler;S. Gardiner;E. Tiesinga;P. Julienne
中科院分区：
文献类型：
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作者：
K. Góral;T. Koehler;S. Gardiner;E. Tiesinga;P. Julienne
我们详细考虑的情况下，施加一个随时间变化的外部磁场的87 Rb原子玻色-爱因斯坦凝聚体保持在一个谐波陷阱，以清除原子间的相互作用通过Feshbach共振产生双原子分子。为此，我们引入了一个最小的两体哈密顿依赖于Feshbach共振，它准确地确定所有的低能量二元散射观测值，特别是只有两个原子的分子转换效率的五个可测量的参数。基于这种微观碰撞现象的描述，我们使用多体理论的科勒和伯内特（2002年物理修订A 65 033601），以研究在一个87 Rb玻色-爱因斯坦凝聚体中的分子的协会在一个线性通道的磁场强度通过100 mT的Feshbach共振的效率。我们探索不同的，实验上可访问的，参数制度，并比较预测的朗道-齐纳，配置相互作用，和两个级别的平均场计算与微观多体方法。我们的比较研究揭示了一个显着的不敏感性的分子转换效率相对于微观二元碰撞物理的细节和相干性质的玻色-爱因斯坦凝聚气体，只要磁场强度是线性变化的。我们提供了这种普遍性的分子生产实现的线性斜坡的磁场强度的原因，并确定由Mies等人（2000年物理评论A 61 022721）确定的朗道-齐纳系数作为主要参数，控制的效率。
We consider in detail the situation of applying a time-dependent external magnetic field to a 87Rb atomic Bose–Einstein condensate held in a harmonic trap, in order to adiabatically sweep the interatomic interactions across a Feshbach resonance to produce diatomic molecules. To this end, we introduce a minimal two-body Hamiltonian depending on just five measurable parameters of a Feshbach resonance, which accurately determines all low-energy binary scattering observables, in particular, the molecular conversion efficiency of just two atoms. Based on this description of the microscopic collision phenomena, we use the many-body theory of Kohler and Burnett (2002 Phys. Rev. A 65 033601) to study the efficiency of the association of molecules in a 87Rb Bose–Einstein condensate during a linear passage of the magnetic-field strength across the 100 mT Feshbach resonance. We explore different, experimentally accessible, parameter regimes, and compare the predictions of Landau–Zener, configuration interaction, and two-level mean-field calculations with those of the microscopic many-body approach. Our comparative studies reveal a remarkable insensitivity of the molecular conversion efficiency with respect to both the details of the microscopic binary collision physics and the coherent nature of the Bose–Einstein condensed gas, provided that the magnetic-field strength is varied linearly. We provide the reasons for this universality of the molecular production achieved by linear ramps of the magnetic-field strength, and identify the Landau–Zener coefficient determined by Mies et al (2000 Phys. Rev. A 61 022721) as the main parameter that controls the efficiency.