Properties of spin–orbit-coupled Bose–Einstein condensates
Properties of spin–orbit-coupled Bose–Einstein condensates
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DOI：
10.1007/s11467-016-0560-y
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发表时间：
2016-06
影响因子：
7.5
通讯作者：
Yongping Zhang;M. Mossman;T. Busch;P. Engels;Chuanwei Zhang
中科院分区：
文献类型：
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作者：
Yongping Zhang;M. Mossman;T. Busch;P. Engels;Chuanwei Zhang
近年来，自旋轨道耦合超冷原子气体的实验和理论研究得到了迅速发展和扩展。在这里，我们回顾了一些进展，无论是由我们自己的工作开创，帮助奠定了基础，或开发了新的和相关的技术。在研究了所有相关的自旋-轨道耦合参数的实验可及性之后，我们讨论了自旋-轨道耦合玻色-爱因斯坦凝聚体（BEC）在各种物理情况下的基本性质和一般应用。对于简谐俘获的情况，我们表明基态相变是一个Dicke型过程，自旋轨道耦合BEC提供了一个独特的平台来模拟和研究迪凯模型和迪凯相变。对于一个均匀的BEC，我们讨论的集体激发，这已被观察到的实验使用布拉格光谱。它们具有一个类似于Roton的最小值，其软化提供了一个潜在的机制来理解基态相变。另一方面，如果集体动力学的自旋-轨道耦合参数的突然淬火激发，我们表明，由此产生的集体动力学可以与著名的Zitterbewegung在相对论领域。最后，我们讨论了BEC加载到周期光学势中的情况。在这里，自旋轨道耦合产生孤立的平坦带内的最低布洛赫带，而系统的非线性导致这些布洛赫波的动力学不稳定性。这种不稳定性的实验验证说明了系统中缺乏伽利略不变性。
The experimental and theoretical research of spin–orbit-coupled ultracold atomic gases has advanced and expanded rapidly in recent years. Here, we review some of the progress that either was pioneered by our own work, has helped to lay the foundation, or has developed new and relevant techniques. After examining the experimental accessibility of all relevant spin–orbit coupling parameters, we discuss the fundamental properties and general applications of spin–orbit-coupled Bose–Einstein condensates (BECs) over a wide range of physical situations. For the harmonically trapped case, we show that the ground state phase transition is a Dicke-type process and that spin–orbit-coupled BECs provide a unique platform to simulate and study the Dicke model and Dicke phase transitions. For a homogeneous BEC, we discuss the collective excitations, which have been observed experimentally using Bragg spectroscopy. They feature a roton-like minimum, the softening of which provides a potential mechanism to understand the ground state phase transition. On the other hand, if the collective dynamics are excited by a sudden quenching of the spin–orbit coupling parameters, we show that the resulting collective dynamics can be related to the famous Zitterbewegung in the relativistic realm. Finally, we discuss the case of a BEC loaded into a periodic optical potential. Here, the spin–orbit coupling generates isolated flat bands within the lowest Bloch bands whereas the nonlinearity of the system leads to dynamical instabilities of these Bloch waves. The experimental verification of this instability illustrates the lack of Galilean invariance in the system.