弱联接玻色爱因斯坦凝聚体中势垒宽度对非线性耦合及其动力学的影响

The Effect of the Barrier Width on the Nonlinear Coupling and Dynamics of Weakly Coupling Bose-Einstein Condensates

利用解析与数值方法,对处于对称双势阱中的玻色爱因斯坦凝聚体中,势垒宽度对系统非线性耦合及其动力学的影响进行了研究.研究发现当势垒宽度较大时,系统的线性耦合强度可迅速减小;在势垒宽度大于0.3且非线性强度较大时,线性耦合强度远小于非线性耦合项,此时玻色约瑟夫森结模型的动力学特性由非线性耦合强度来决定.同时对势垒宽度对BEC约瑟夫森振荡的周期和发生宏观量子自俘获时的非线性临界值进行了详细的研究.

By using analytical and numerical methods,the effects of barrier width on the strength of nonlinear coupling and the dynamics of Bose-Einstein Condensates with symmetrical double square well were investigated.The results show that the linear coupling could be very small once the barrier width is large.When the width is larger than 0.3 and nonlinear parameters larger,the linear coupling can be safely neglected.In this case,the dynamics character of Bose-Jsoephson model is determined only by nonlinear coupling strength.Furthermore,the effects of this width on the period of the nonlinear Josephson oscillation and the nonlinear threshold value in macroscopic quantum self-trapping were presented in details.