三体作用下准一维玻色-爱因斯坦凝聚体中表面带隙孤子及其稳定性  

Surface gap solitons and their stabilities in quasi-1D Bose-Einstein condensate with three-body interactions

作　　者：王青青 周玉珊 王静 樊小贝 邵凯花 赵月星 宋燕 石玉仁 Wang Qing-Qing;Zhou Yu-Shan;Wang Jing;Fan Xiao-Bei;Shao Kai-Hua;Zhao Yue-Xing;Song Yan;Shi Yu-Ren(Laboratory of Atomic Molecular Physics and Functional Material,College of Physics and Electronic Engineering,Northwest Normal University,Lanzhou 730070,China)

机构地区：[1]西北师范大学物理与电子工程学院,甘肃省原子分子物理与功能材料重点实验室,兰州730070

出　　处：《物理学报》2023年第10期112-123,共12页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12065022,12147213,11565021)资助.

摘　　要：数值研究了具有三体相互作用的均匀介质界面和半无限雅克比椭圆正弦势下准一维玻色-爱因斯坦凝聚体(Bose-Einstein condensate,BEC)中的表面带隙孤子及其稳定性.在平均场近似下,其动力学行为可用3次-5次Gross-Pitaevskii方程描述.首先用牛顿-共轭梯度法寻找表面带隙孤子,发现表面亮孤子仅当化学势小于0时才可于带隙内激发,但表面扭结孤子和气泡孤子既可存在于带隙中也可存在于能带中.然后采用线性稳定性分析和非线性动力学演化研究了孤子的稳定性,结果表明三体相互作用会明显影响表面亮孤子的稳定性,表面扭结孤子既有稳定的也有不稳定的,但表面气泡孤子均不稳定.The dynamical stability properties of surface gap solitons in quasi-one-dimensional Bose-Einstein condensate loaded in the interface between uniform media and a semi-infifinite Jacobian elliptic sine potential with three-body interactions are investigated numerically.Under the mean-fifield approximation,the dynamical behaviors can be well-described by the nonlinear cubic-quintic Gross-Pitaevskii equation.Firstly,many kinds of surface gap solitons,including the surface bright solitons,surface kink solitons and surface bubble solitons,are obtained numerically by the Newton-conjugate gradient method.The surface bright solitons can be excited in the gap only for the case that the chemical potential is negative and their power is beyond a threshold value.All of them are not bifurcated from the Bloch band.A class of surface solitons with new structures,named the surface dark solitons,can be formed when the three-body interactions are taken into account.The surface dark solitons can exist not only in gap but also in band.The numerical results indicate that the amplitude of the surface gap solitons decreases as the three-body interaction strength increases.Both linear stability analysis and nonlinear dynamical evolution methods are applied to investigate the stability properties of surface gap solitons.For surface bright solitons in the semi-infinite gap,there is a critical value when the chemical potential is given.The surface bright solitons become linearly stable as the three-body interaction exceeds the critical value,or they are linearly unstable.Therefore,the three-body interaction strength plays an important role on the stability of surface gap solitons.One can change the dynamical behaviors of surface gap solitons by adjusting the three-body interaction strength in experiments.Numerical results also show that both stable and unstable surface kink solitons exist.However,all the surface bubble solitons are unstable.

关 键 词：玻色-爱因斯坦凝聚体 表面带隙孤子 三体相互作用 牛顿共轭梯度法 

分 类 号：O469[理学—凝聚态物理]