Harmonic and subharmonic association of universal dimers in a thermal gas
Harmonic and subharmonic association of universal dimers in a thermal gas
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热气体中通用二聚体的谐波和次谐波关联
DOI：
10.1103/physreva.92.013425
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发表时间：
2015
影响因子：
2.9
通讯作者：
E. Braaten
中科院分区：
文献类型：
--
作者：
A. Mohapatra;E. Braaten
在超冷原子的气体中，其散射长度由磁费什巴赫共振控制，原子可以通过振荡磁场结合成通用二聚体。除了频率接近由二聚体结合能确定的频率的谐波共振之外，还存在频率为该频率一半的次谐波共振。如果热气体含有二聚体，它们可以通过振荡磁场解离成未结合的原子。我们表明，可以通过将振荡磁场视为与接触算子成比例的正弦时间相关扰动来计算缔合和解离的转变率。通过接触算子的转移矩阵元素考虑多体效应。我们分析计算了原子热气体中缔合和二聚体热气体中解离的谐波和次谐波跃迁速率。
In a gas of ultracold atoms whose scattering length is controlled by a magnetic Feshbach resonance, atoms can be associated into universal dimers by an oscillating magnetic field. In addition to the harmonic resonance with frequency near that determined by the dimer binding energy, there is a subharmonic resonance with half that frequency. If the thermal gas contains dimers, they can be dissociated into unbound atoms by the oscillating magnetic field. We show that the transition rates for association and dissociation can be calculated by treating the oscillating magnetic field as a sinusoidal time-dependent perturbation proportional to the contact operator. Many-body effects are taken into account through transition matrix elements of the contact operator. We calculate both the harmonic and subharmonic transition rates analytically for association in a thermal gas of atoms and dissociation in a thermal gas of dimers.