光晶格中自旋-轨道耦合超冷费米气体的超流性质研究

The experimental realization of spin-orbit coupling in ultracold atoms has broaden the research visual field of ultracold atomic system as the platform of quantum simulation, the studies on the novel quantum state and peculiar properties in spin-orbit coupled ultracold atoms have been one of the international hot research topics currently. By combing the analytical calculation and numerical simulation methods, this project is devoted to studying the superfluidity of spin-orbit coupled ultracold Fermi gases in optical lattice. This project mainly analyzes the affects of spin-orbit coupling on the superfluidity stability and collective excitation of ultracold Fermi gases in moving optical lattice, and explores the novel quantum states and quantum phase transitions induced by the spin-orbit coupling in triangle and hexagonal optical lattices. On the one hand, this project expects to reveal the mechanism how the spin-orbit coupling affects the critical superfluidity velocity and excitation spectrum of Fermi gases in moving optical lattice. On the other hand, this project will summary the universal laws of the affects of spin-orbit coupling on Fermi atomic pairing and superfluidity density in triangle or hexagonal optical lattices, and discover the novel quantum states and determine the relation between the critical point of quantum phase transition and spin-orbit coupling. The results given by this project would have meaning to deeply understand the novel quantum phenomena induced by spin-orbit coupling, and it will provide new thought to simulate the quantum many-body system in traditional condensed physics by using the ultracold atomic platform.

自旋-轨道耦合在超冷原子中的实验实现拓宽了超冷原子系统作为量子仿真平台的研究视野，其新颖量子态和奇异物性的研究已成为了当前国际上的热点课题之一。本项目针对光晶格中超冷费米气体的超流问题，采用解析和数值相结合的方法，研究自旋-轨道耦合对体系超流性质的影响。项目主要分析移动光晶格中自旋－轨道耦合对费米气体的超流稳定性及集体激发的影响，探索三角及六角复杂光晶格中自旋-轨道耦合可能诱导的新奇量子态和量子相变。项目预期将揭示移动光晶格中自旋－轨道耦合对费米气体超流临界速度和激发谱的影响机制，总结归纳三角及六角光晶格中自旋-轨道耦合对费米原子配对及超流密度产生影响的一般规律，发现新奇量子态，确定量子相变临界点与自旋-轨道耦合的关系，并给出体系的相图。项目研究成果对深入理解自旋-轨道耦合诱导新奇量子现象的物理机制具有重要意义，为利用超冷原子平台模拟和仿真传统凝聚态物理中的量子多体系统提供重要途径。

本项目围绕自旋-轨道耦合超冷原子量子气体，利用解析计算和数值模拟相结合的研究手段，分别研究了光晶格、均匀体系、旋转参考系和光学微腔中费米气体及玻色气体的新奇量子态和非线性物质波现象。研究获得了以下成果：（1）在光晶格中，发现自旋-轨道耦合费米气体中存在着拓扑超流态及Majorana零模，给出了多层自旋-轨道耦合玻色-爱因斯坦凝聚体的基态相图，分析了自旋为2的旋量玻色气体的能量和动力学稳定性；（2）在均匀体系中，发现自旋-轨道耦合将驱动孤子做周期性振荡运动，双组份玻色-爱因斯坦凝聚体中环状暗孤子将塌缩为两对涡旋-反涡旋对；（3）在旋转参考系下，发现双组份偶极玻色-爱因斯坦凝聚的基态存在着许多有趣的超流涡旋晶格态，并给出了其基态相图；（4）在光学微腔中，发现在自旋-轨道耦合费米气中，光和原子的耦合将导致双原子极化子。本项目在执行期间，已发表的标注本项目致谢的SCI论文9篇。