Spin - Orbital Angular Momentum Coupled Ultra-cold Atomic Gases

自旋-轨道角动量耦合超冷原子气体

• 批准号: 1505496
• 负责人: Chuanwei Zhang
• 金额: $ 24万
• 依托单位: University of Texas at Dallas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1505496&HistoricalAwards=false
• 关键词: Spin; Orbital; Angular; Momentum; Coupled

The advances of modern electrical devices are often driven by the discovery of new quantum materials. In many materials, the coupling between electron spins and their motional degrees of freedom (linear momentum and orbital angular momentum), i.e., spin-orbit coupling, plays a crucial role in the underlying material properties. Understanding the effects of spin-orbit coupling in a controllable platform could provide important guidelines for future design and discovery of new quantum materials with desirable properties and functionalities. In this context, ultra-cold atomic gases offer such a controllable platform for material design and discovery with unprecedented level of control and precision in experiments. Previous research has realized one type of spin-orbit coupling (the coupling between spin and linear momentum) for ultra-cold atoms, which now becomes one major research frontier in physics. However, another important and fundamental type of spin-orbit coupling, the coupling between spin and orbital angular momentum (SOAM coupling), has not been explored for ultra-cold atomic gases. In this project, the generation of SOAM coupling for ultra-cold atoms and their applications in engineering new quantum states will be studied. The study of such highly controllable SOAM coupled cold atomic platform will in turn influence the future electronic material design and discovery. This work will not only pave the way for coherent control of cold atomic systems for many important applications (e.g., material design, quantum computation, precision measurement, etc.), but will also influence fundamental research in cold atomic and condensed matter physics. The major objective of this project is to investigate the generation and applications of SOAM coupling in ultra-cold atomic gases using higher order Laguerre-Gaussian (LG) laser modes. Another goal is to study the cold atomic physics with spatially varying spin-linear-momentum (SLM) coupling using higher order Hermit-Gaussian (HG)) laser modes. Specific tasks include: 1) Study the generation of SOAM coupling or spatially varying SLM coupling using LG or HG Raman laser modes; 2) Investigate ground states and collective dynamics of cold atoms in the presence of SOAM coupling and HG-SLM coupling; c) Explore novel quantum phases induced by SOAM or HG-SLM couplings for both bosons and fermions. Various numerical and analytical methods (e.g., mean field approximation, time-evolving-block-decimation algorithm, perturbation theory, etc.) will be applied. The work will provide a diverse platform for both graduate and undergraduate students to explore theoretical cold atomic and condensed matter physics. In addition, this effort will include outreach activities for K-12 students and involvement of students from under-represented groups, such as women and minority students.

现代电子设备的进步通常是由新量子材料的发现推动的。在许多材料中，电子自旋和它们的运动自由度（线动量和轨道角动量）之间的耦合，即，自旋-轨道耦合在底层材料性质中起着至关重要的作用。了解可控平台中的自旋轨道耦合效应可以为未来设计和发现具有理想性能和功能的新量子材料提供重要指导。在这种背景下，超冷原子气体为材料设计和发现提供了这样一个可控平台，具有前所未有的控制水平和实验精度。以往的研究已经实现了超冷原子的一种自旋-轨道耦合（自旋与线动量之间的耦合），这是目前物理学的一个重要研究前沿。然而，另一种重要的和基本的自旋-轨道耦合，自旋和轨道角动量之间的耦合（SOAM耦合），还没有被探索用于超冷原子气体。本计画将研究超冷原子的SOAM耦合产生及其在工程新量子态中的应用。这种高度可控的SOAM耦合冷原子平台的研究将反过来影响未来电子材料的设计和发现。这项工作不仅将为许多重要应用的冷原子系统的相干控制铺平道路（例如，材料设计、量子计算、精密测量等），也将影响冷原子和凝聚态物理学的基础研究。 本计画的主要目的是探讨高阶拉盖尔-高斯（LG）雷射模式在超冷原子气体中产生SOAM耦合的方法及其应用。另一个目标是利用高阶厄米-高斯（HG）激光模式研究空间变化自旋-线动量（SLM）耦合的冷原子物理。具体任务包括：1）研究利用LG或HG拉曼激光模式产生SOAM耦合或空间变化的SLM耦合; 2）研究SOAM耦合和HG-SLM耦合下冷原子的基态和集体动力学; 3）探索玻色子和费米子的SOAM或HG-SLM耦合诱导的新量子相位。各种数值和分析方法（例如，平均场近似、时变分块抽取算法、微扰理论等）将被应用。这项工作将为研究生和本科生探索理论冷原子和凝聚态物理提供一个多样化的平台。此外，这项工作将包括为K-12学生开展外联活动，并让妇女和少数民族学生等代表性不足的群体的学生参与。

项目成果

Momentum space Aharonov-Bohm interferometry in Rashba spin-orbit coupled Bose-Einstein condensates

• DOI: 10.1209/0295-5075/123/10005
• 发表时间: 2017-10
• 期刊: Europhysics Letters
• 作者: Junpeng Hou;Xiwang Luo;K. Sun;Chuanwei Zhang