Floquet topological phases in a spin- 1/2 double kicked rotor
Floquet topological phases in a spin- 1/2 double kicked rotor
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DOI：
10.1103/physreva.97.063603
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发表时间：
2018-03
影响因子：
2.9
通讯作者：
Longwen Zhou;J. Gong
中科院分区：
文献类型：
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作者：
Longwen Zhou;J. Gong
双踢转子模型是范式踢转子模型在量子混沌研究中物理上可实现的扩展。早在Floquet拓扑相位的概念广为人知之前，双踢转子模型中霍夫施塔特蝴蝶谱的发现[J]。王和龚，物理学。Rev. A 77, 031405(2008)]已经提出了周期性驱动对非常规拓扑物质生成的重要性。在这项工作中，我们研究了具有额外自旋1/2自由度的双踢转子的Floquet拓扑相。后者最近通过将Rb87凝聚体加载到周期性脉冲光学晶格中，在量子踢动转子中进行了实验设计。在非共振条件下，自旋-1/2双踢转子由于其内外自由度的相互作用，具有丰富的拓扑相位。这些拓扑相中的每一个都由一对绕组数表征，它们的组合预测了系统中拓扑保护的0和\pi准能量边缘态的数量。通过调整抽芯强度，可以很容易地找到具有任意大绕组数的拓扑相。我们讨论了在踢入的Rb87凝聚体中实现该模型的实验方案，并建议通过测量动量空间中的平均手性位移来检测其拓扑不变量。
The double kicked rotor model is a physically realizable extension of the paradigmatic kicked rotor model in the study of quantum chaos. Even before the concept of Floquet topological phases became widely known, the discovery of the Hofstadter butterfly spectrum in the double kicked rotor model [J. Wang and J. Gong, Phys. Rev. A 77, 031405 (2008)] already suggested the importance of periodic driving to the generation of unconventional topological matter. In this work, we explore Floquet topological phases of a double kicked rotor with an extra spin-1/2 degree of freedom. The latter has been experimentally engineered in a quantum kicked rotor recently by loading Rb87 condensates into a periodically pulsed optical lattice. Under the on-resonance condition, the spin-1/2 double kicked rotor admits fruitful topological phases due to the interplay between its external and internal degrees of freedom. Each of these topological phases is characterized by a pair of winding numbers, whose combination predicts the number of topologically protected 0 and \pi-quasienergy edge states in the system. Topological phases with arbitrarily large winding numbers can be easily found by tuning the kicking strength. We discuss an experimental proposal to realize this model in kicked Rb87 condensates, and suggest to detect its topological invariants by measuring the mean chiral displacement in momentum space.