Dynamics of spin-1 bosons in an optical lattice: Spin mixing, quantum-phase-revival spectroscopy, and effective three-body interactions
Dynamics of spin-1 bosons in an optical lattice: Spin mixing, quantum-phase-revival spectroscopy, and effective three-body interactions
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DOI：
10.1103/physreva.88.023602
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发表时间：
2013-03
影响因子：
2.9
通讯作者：
K. W. Mahmud;E. Tiesinga
中科院分区：
文献类型：
--
作者：
K. W. Mahmud;E. Tiesinga
我们研究了自旋为1的原子在周期性光晶格势和外部磁场中的量子猝灭情况下的动力学，在量子猝灭情况下，我们从浅晶格势中的超流基态开始，突然提高晶格深度。由此产生的非平衡态的时间演化显示了物质波相干性的集体振荡和复苏振荡以及自旋布居的振荡。我们发现，这两种类型的振荡的复杂模式揭示了超流和磁性的初始多体基态的细节。此外，我们还证明了自旋相关和自旋无关的原子-原子相互作用的强度可以从观测中推断出来。描述最终深晶格物理的哈密顿量不仅包含两体相互作用，而且还包含有效的多体相互作用，这是由于虚激发到更高的能带而产生的。我们推导了自旋为1的原子的有效的自旋相关的三体相互作用参数，并描述了如何影响自旋混合。旋量原子是独特的，在这个意义上，多体相互作用是直接明显的，除了在原位的数量密度的动量分布。我们处理反铁磁（例如$^{23}$Na原子）和铁磁（例如$^{87}$Rb和$^{41}$K）凝聚体。
We study the dynamics of spin-1 atoms in a periodic optical-lattice potential and an external magnetic field in a quantum quench scenario where we start from a superfluid ground state in a shallow lattice potential and suddenly raise the lattice depth. The time evolution of the non-equilibrium state, thus created, shows collective collapse-and-revival oscillations of matter-wave coherence as well as oscillations in the spin populations. We show that the complex pattern of these two types of oscillations reveals details about the superfluid and magnetic properties of the initial many-body ground state. Furthermore, we show that the strengths of the spin-dependent and spin-independent atom-atom interactions can be deduced from the observations. The Hamiltonian that describes the physics of the final deep lattice not only contains two-body interactions but also effective multi-body interactions, which arise due to virtual excitations to higher bands. We derive these effective spin-dependent three-body interaction parameters for spin-1 atoms and describe how spin-mixing is affected. Spinor atoms are unique in the sense that multi-body interactions are directly evident in the in-situ number densities in addition to the momentum distributions. We treat both antiferromagnetic (e.g. $^{23}$Na atoms) and ferromagnetic (e.g. $^{87}$Rb and $^{41}$K) condensates.