玻色-爱因斯坦凝聚中的非正则涡旋态及其动力学  

Noncanonical vortex states and dynamics in Bose-Einstein condensates

作　　者：邢健崇 张文静 杨涛[1,2,3] Xing Jian-Chong;Zhang Wen-Jing;Yang Tao(Shaanxi Key Laboratory for Theoretical Physics Frontiers,Institute of Modern Physics,Northwest University,Xi’an 710127,China;School of Physics,Northwest University,Xi’an 710127,China;Peng Huanwu Center for Fundamental Theory(Xi’an),Xi’an 710127,China)

机构地区：[1]西北大学现代物理研究所,陕西省理论物理前沿重点实验室,西安710127 [2]西北大学物理学院,西安710127 [3]彭桓武高能基础理论研究中心(西安),西安710127

出　　处：《物理学报》2023年第10期95-104,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12175180,11934015);瞬态光学与光子技术国家重点实验室开放基金(批准号:SKLST202010);陕西省重大基础研究计划(批准号:2017KCT-12,2017ZDJC-32);陕西基础科学(数学、物理学)研究院项目(批准号:22JSZ005)资助的课题.

摘　　要：玻色-爱因斯坦凝聚中由于非线性相互作用引起的涡旋激发态一直是超冷原子研究的热点.然而相关研究都集中在具有整数拓扑荷的正则涡旋态.本文研究了具有幂指数、新型幂指数和振荡型三种相位分布的非正则涡旋光与凝聚体相互作用而产生的非正则涡旋态凝聚体的动力学性质.研究表明非正则涡旋具有动力学不稳定性,其密度分布显著依赖于光场相位结构参数.不同非正则涡旋衰变形成具有不同分布的正则涡旋簇,展现出丰富的动力学激发斑图.特别是新型幂指数非正则涡旋态衰变后会在凝聚体内形成稳定的正多边形正则涡旋簇结构.由于非正则涡旋光的相位结构破坏了凝聚体的旋转对称性,凝聚体的角动量不再是量子化的,且其随光场方位角幂次或振荡频率的变化与相应的非正则涡旋光场自身演化具有明显差别.在动力学演化过程中,具有新型幂指数相位的非正则涡旋态凝聚体质心保持不变,而对于具有幂指数和振荡型相位的非正则涡旋态凝聚体,两者的质心轨迹是一个中心为坐标原点的非标准椭圆.Vortex excitations triggered by nonlinear interactions in Bose-Einstein condensates have attracted interest in the study of ultracold atoms.However,most studies focus on canonical vortex states with integer topological charges.In this paper,we study the dynamic properties of noncanonical vortex condensates with three phase distributions:power-exponent,new type power-exponent and oscillation type.The results show that the noncanonical vortices are dynamic unstable and their density distributions obviously depend on the phase parameters of the initial optical phase masks.Different noncanonical vortices decay into canonical clusters with diverse configurations showing rich topological excitation patterns.In particular,a new power exponential noncanonical vortex state decays into a stable canonical polygonal vortex cluster structure.Because the phase structures of the noncanonical optical vortices destroy the rotational symmetry of the condensate,the angular momentum of the condensate is no longer quantized,and its value changes with the power of the azimuthal angle of the optical field or the oscillation frequency,which is obviously different from the evolution of the corresponding noncanonical vortex optical field itself.In the dynamical process,the center-of-mass trajectory of noncanonical vortex condensates with the new type of power exponent phase is always a point,while for the noncanonical vortex condensates with power exponent and oscillating phase,the center-of-mass trajectories are ellipses centering at the origin of coordinates.

关 键 词：玻色-爱因斯坦凝聚 非正则涡旋态 正则涡旋簇 角动量 质心轨迹 

分 类 号：O469[理学—凝聚态物理]