Dynamics in spinor condensates tuned by a microwave dressing field
Dynamics in spinor condensates tuned by a microwave dressing field
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DOI：
10.1103/physreva.89.023608
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发表时间：
2013-10
影响因子：
2.9
通讯作者：
Lichao Zhao;Jie Jiang;T. Tang;M. Webb;Yingmei Liu
中科院分区：
文献类型：
--
作者：
Lichao Zhao;Jie Jiang;T. Tang;M. Webb;Yingmei Liu
实验研究了钠反铁磁旋量凝聚体在非共振微波脉冲作用下的自旋动力学。与磁场相比，微波修整场使我们能够在负净二次塞曼位移q_{\rm net}$的影响下探索丰富的自旋动力学。我们找到了一个实验信号来确定$q_{\rm net}$的符号，并在每个$q_{\rm net}$上观察到谐波自旋布居振荡，除了在相空间中自旋振荡周期发散的每个分界线附近。在负的和正的$q_{\rm net}$区域中，我们也观察到每个分界线和磁化强度之间的显著不同的关系。我们的数据证实了一个重要的预测来自平均场理论：自旋1凝聚的自旋混合动力学实质上取决于$q_{\rm net}$和自旋相关的相互作用能的比值的符号。因此，这项工作可能是第一个只使用一种原子物种来揭示平均场自旋动力学，特别是分界线，预计在自旋1反铁磁和铁磁旋量凝聚中会出现不同的情况。
We experimentally study spin dynamics in a sodium antiferromagnetic spinor condensate with off-resonant microwave pulses. In contrast to a magnetic field, a microwave dressing field enables us to explore rich spin dynamics under the influence of a negative net quadratic Zeeman shift $q_{\rm net}$. We find an experimental signature to determine the sign of $q_{\rm net}$, and observe harmonic spin population oscillations at every $q_{\rm net}$ except near each separatrix in phase space where spin oscillation period diverges. In the negative and positive $q_{\rm net}$ regions, we also observe a remarkably different relationship between each separatrix and the magnetization. Our data confirms an important prediction derived from the mean-field theory: spin-mixing dynamics in spin-1 condensates substantially depends on the sign of the ratio of $q_{\rm net}$ and the spin-dependent interaction energy. This work may thus be the first to use only one atomic species to reveal mean-field spin dynamics, especially the separatrix, which are predicted to appear differently in spin-1 antiferromagnetic and ferromagnetic spinor condensates.