二维玻色-爱因斯坦凝聚中平头孤立子稳定性的研究

Study on Stability of Flat-top Solitons in A Two-dimensional Bose-Einstein Condesates

利用静态和含时变分法研究了二维圆对称玻色-爱因斯坦凝聚中"平头"孤立子的稳定性.采用静态变分法给出了确定稳定孤立子参数的方程组,并给出了只考虑原子之间两体相互作用时稳定孤立子的振幅、宽度和化学势的解析表达式;采用含时变分法给出孤立子宽度随时间演化的微分方程和有效势能的解析表达式.结合静态和含时变分法对体系的稳定性进行分析,结果表明:在原子之间存在两体排斥和吸引相互作用时均可以形成稳定的"平头"孤立子;三体相互作用对体系的稳定性起调整作用(增强或减弱体系的稳定性);相对于三体相互作用,高阶相互作用对体系的稳定性有重要影响.

Stability of flat-top solitons in a two-dimensional Bose-Einstein condesates has been studied by a variational approximation and numerical simulations.The equations which to determine the relation between system parameters including the amplitude,width and chemical potential are derived by the static variational approximations.The effective potential for the stability analysis of the system is derived using the flat-top type trial wave function and the stable criteria is gived through this effective potential.It is demonstrated that the flat-top type trial wave function,three-body and high-order interactions play different roles in the stability of the system.The high-order interaction has an important influence to the stability but the others play a regulatory role on the stability.