Spin-momentum coupled Bose-Einstein condensates with lattice band pseudospins.
Spin-momentum coupled Bose-Einstein condensates with lattice band pseudospins.
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DOI：
10.1038/ncomms10867
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发表时间：
2016-02-29
影响因子：
16.6
通讯作者：
Engels P
中科院分区：
文献类型：
--
作者：
Khamehchi MA;Qu C;Mossman ME;Zhang C;Engels P
自旋-动量耦合的量子模拟是拓扑相出现的关键因素，目前正引起人们的极大兴趣。在以前的量子气体实验中，通常选择两个原子超精细态作为赝自旋。在这里，我们报告的自旋动量耦合的观察实现加载玻色-爱因斯坦凝聚到周期性驱动的光学晶格。作为赝自旋的静态晶格的s带和p带通过额外的移动晶格耦合，该移动晶格引起两个赝自旋之间的动量依赖耦合，导致s-p混合Floquet-Bloch带。我们调查的能带结构，通过测量的准动量的玻色-爱因斯坦凝聚体不同的速度和强度的移动晶格，并比较我们的测量理论预测。以晶格带为赝自旋实现自旋-动量耦合，为利用杂化轨道带设计新的量子物质铺平了道路。 超冷原子的光学捕获允许对通常在凝聚态系统中发现的现象进行模拟和受控探索。在这里，作者证明了超冷原子的玻色-爱因斯坦凝聚体中晶格带赝自旋之间的自旋-轨道耦合。
The quantum emulation of spin-momentum coupling, a crucial ingredient for the emergence of topological phases, is currently drawing considerable interest. In previous quantum gas experiments, typically two atomic hyperfine states were chosen as pseudospins. Here, we report the observation of a spin-momentum coupling achieved by loading a Bose-Einstein condensate into periodically driven optical lattices. The s and p bands of a static lattice, which act as pseudospins, are coupled through an additional moving lattice that induces a momentum-dependent coupling between the two pseudospins, resulting in s–p hybrid Floquet-Bloch bands. We investigate the band structures by measuring the quasimomentum of the Bose-Einstein condensate for different velocities and strengths of the moving lattice, and compare our measurements to theoretical predictions. The realization of spin-momentum coupling with lattice bands as pseudospins paves the way for engineering novel quantum matter using hybrid orbital bands. The optical trapping of ultracold atoms allows for the simulation and controlled exploration of phenomena normally found in condensed matter systems. Here, the authors demonstrate spin–orbit coupling between lattice band pseudospins in a Bose-Einstein condensate of ultracold atoms.