双层偶极量子气体新特性及其动力学研究

The research and development of new quantum storage devices has always been a hot issue for researchers, but there are some problems in the study of it, such as the problem of impurity and regulation and so on. However, ultra-cold atomic gas, as its precision regulation and measurement, provides an important research platform for quantum simulation, especially for the dipolar quantum gas, which is very sensitive to the shape of the external potential well. In this project, we proposes to use a bilayer dipolar quantum gas to simulate the three-layer nano-magnetic. We will discusse the quantum fluctuation and collective excitation of the system, and study its stability, by solving the GP coupling equation under the theory of fluctuation dissipation. And then, we will discusses the competitive relationship between spin orbit coupling interaction and dipole interaction in double-layer dipolar quantum gas. Finally, we will propose a model of asymmetric double-layer dipolar quantum gas and study the spin structure of ground state and the quenching kinetic behavior, by precisely regulate the shape and interaction parameters of the trap. This project is expected to provide a new idea for the study of topological spin structure and provide a theoretical scheme for the experimental inquiry of quantum storage.

研究和开发新型量子存储设备一直是研究者们关注的热点话题，但用传统凝聚体材料去研究它时，存在材料不纯净、参数难以精确调控等问题，而超冷原子气体的“纯净”和易调控特性为量子模拟提供了重要的研究平台，尤其是对外势阱形状非常敏感的偶极量子气体。本项目拟提出用双层偶极量子气体模拟三层纳米磁片的模型，在零温极限下，通过求解基于涨落耗散理论的耦合GP方程，讨论其量子涨落和集体激发性质，并分析该系统的稳定性；其次，探讨双层偶极量子气体中自旋轨道耦合与偶极相互作用的竞争关系；最后，提出非对称双层偶极量子气体模型，通过精确调控束缚势阱的形状和相互作用参数，研究此模型的基态自旋结构以及淬火动力学行为。本项目有望为拓扑自旋结构的研究提供新思路，为量子存储的实验探究提供理论方案。

高阶怪波精的求解较为困难，且难以在实验上生成，寻求更简单、容易产生高阶怪波的方确解法迫在眉睫。基于这些动机，我们发现了一个理想的实验平台--玻色爱因斯坦凝聚体，它可以非常方便地用平均场近似的Gross-Pitaevskii (GP)方程描述，并且相互作用参数可以通过实验操作原子密度和Feshbach共振技术等进行调节。我们选择含有偏移量的高斯波包做为初始条件，数值地研究了一维两分量玻色爱因斯坦凝聚体中的怪波碰撞事件，即提出了一种简单且易于实现的生成高阶怪波的方案。研究结果表明二阶怪波是否能成功激发与一阶怪波相遇的位置和时间有关。只有当两个怪波的峰值同时在同一位置相遇时，才能触发标准的二阶怪波，其结构与精确解很好地吻合。此外，我们还证明了这些结果同样适用于次一阶怪波的碰撞。近期，我们还研究了三分量玻色爱因斯坦凝聚体中的怪波碰撞特性。该工作不仅揭示了怪波的碰撞特性，而且为实验的实现提供了一种生成高阶怪波的可行方案。