【摘要】 提出了一种处理玻色-爱因斯坦凝聚啁啾孤子动力学的拓展变分方法,深入研究了玻色-爱因斯坦凝聚孤子在周期势与抛物势联合作用下的动力学演化,利用拓展变分法给出了解析处理,并和基于分步傅里叶变换的直接数值法进行比较,发现这种拓展变分方法能够充分揭示上述外势场中的玻色-爱因斯坦凝聚啁啾孤子的动力学行为和特征.同时给出了能支持多稳定晶格囚禁玻色-爱因斯坦凝聚啁啾孤子的周期势与抛物势强度比值的临界值和一种通过控制外势场可有选择地移动玻色-爱因斯坦凝聚啁啾孤子的操控方法,这为玻色-爱因斯坦凝聚的实验和应用研究提供了理论参考.更多还原

【Abstract】 An extended variational method for describing the dynamics of a Bose_Einstein condensate(BEC)chirped soliton in the presence of periodic and harmonic potentials is developed.It is shown that the BEC chirped soliton dynamics can be deduced via the extended variational method to a set of four coupled nonlinear differential equations.This deduced set of equations agrees remarkably well with full numerical simulations and highlights the dominant physical interactions in the system,namely amplitude,width,chirp,center-position,and center-frequency dynamics.The extended analytic theory provides a useful,accurate,and greatly simplified description of the governing BEC chirped soliton dynamics.It further gives the critical strength ratio of periodic to harmonic potential necessary to support multiple stable lattice sites for the BEC chirped soliton and demonstrates that the BEC chirped soliton can move selectively from one lattice site to another by simply manipulating the potentials.In addition,some interesting results for the experiments and applications of the BEC are also obtained.更多还原