双组分玻色-爱因斯坦凝聚体中PT对称势下的异步量子Kármán涡街  

Asynchronous quantum Kármán vortex street in two-component Bose-Einstein condensate with PT symmetric potential

作　　者：邵凯花 席忠红 席保龙 涂朴 王青青 马金萍 赵茜 石玉仁[1] Shao Kai-Hua;Xi Zhong-Hong;Xi Bao-Long;Tu Pu;Wang Qing-Qing;Ma Jin-Ping;Zhao Xi;Shi Yu-Ren(College of Physics and Electronic Engineering,Northwest Normal University,Lanzhou 730070,China;College of Physics and Hydropower Engineering,Gansu Normal College for Nationalities,Hezuo 747000,China;College of Intelligent Manufacturing,Sichuan University of Arts and Science,Dazhou 635000,China)

机构地区：[1]西北师范大学物理与电子工程学院,兰州730070 [2]甘肃民族师范学院物理与水电工程系,合作747000 [3]四川文理学院智能制造学院,达州635000

出　　处：《物理学报》2024年第11期37-45,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12065022,12147213)资助的课题。

摘　　要：数值研究了相混合态双组分玻色-爱因斯坦凝聚体(Bose-Einstein condensate,BEC)中PT (parity-time)对称势下的动力学.在障碍势不同的宽度和速度下发现了异步量子Kármán涡街、斜向漂移涡旋偶极子、V字形涡旋对、无规则量子湍流以及各种尾迹的组合模式.研究了作用在移动障碍势上的拖拽力,分析了涡旋对产生的力学机理.在不同障碍势宽度和速度下,系统地模拟了异步量子Kármán涡街和其他尾迹模式的参数区域.同样分析了PT对称势中具有增益-损耗强度的虚部对异步量子Kármán涡街稳定性的影响.最后,提供了一个实现异步量子Kármán涡街的实验方案.The dynamics of a miscible two-component Bose-Einstein condensate(BEC)with PT(parity-time)symmetric potential are investigated numerically.The dynamical behaviors of the system is described by Gross-Pitaevskii(GP)equations under the mean-field theory.Firstly,the ground state of the system is obtained by the imaginary-time propagation method.Then dynamical behaviors are numerically simulated by the time-splitting Fourier pseudo-spectral approach under periodic boundary conditions.By adjusting the width and velocity of the obstacle potential,various patterns such as no vortex,oblique drifting vortex dipole,V-shaped vortex pairs,irregular quantum turbulence and combined modes are studied.It is noted that the shedding vortex pairs in components 1 and 2 are staggered,which is called“the asynchronous quantum Kármán vortex street”.Here,the ratio of the distance between two vortex pairs in one row to the distance between vortex rows is approximately 0.18,which is less than the stability criterion 0.28 of classical fluid.We calculated the drag force acting on the obstacle potential during generation of the asynchronous quantum Kármán vortex street.It is found that periodical oscillation of the drag force is generated via drifting up or down of the vortex pairs.Meanwhile,we analyzed the influence of the imaginary part of the PT symmetric potential with gain-loss for wake.The trajectory and frequency of the vortex are changed,due to the imaginary part breaks the local symmetry of the system.In addition,the imaginary part affects the stability of the asynchronous quantum Kármán vortex street.Lots of numerical simulations are carried out to determine the parameter regions of various vortex shedding modes.We also proposed an experimental protocol to realize the asynchronous quantum Kármán vortex street in the miscible two-component BEC with PT symmetric potential.

关 键 词：玻色-爱因斯坦凝聚体 Kármán涡街 PT对称势 

分 类 号：O41[理学—理论物理]