旋转二维光晶格中玻色-爱因斯坦凝聚体量子涡旋研究

Quantum vortex of Bose-Einstein condensate in rotating two-dimensional optical lattice

基于Gross Pitaevskii(G-P)方程的数值模拟,研究了旋转二维光晶格中玻色-爱因斯坦凝聚气体量子涡旋的动力学性质,分析了光晶格常数d、光晶格深度v_0对量子涡旋的影响。结果表明:随v_0增加量子涡旋形成过程变快,通过计算系统自由能随时间的演化分析了这一动力学行为的物理本质;v_0大于50时出现针钉效应,即量子涡旋被光晶格固定在势能极值点;d大于2.7d_c(d_c为临界常数)时出现涡旋-反涡旋对.

Based on numerical simulation of Gross Pitaevskii（G-P） equation, the dynamical properties of Bose-Einstein condensed gas quantum vortex in a rotating two-dimensional optical lattice are investigated. Influences of optical lattice constant d and optical lattice depth v0 on quantum vortex are analyzed. Results show that the formation process of quantum vortex becomes faster with increasing of v0. The physical essence of this dynamic behavior is analyzed by calculating the evolution of system free energy with time. When v0 is more than 50, there is pinning effect. That is to say, the quantum vortex is fixed on the extreme point of potential energy by optical lattice. When d is greater than 2.7dc （de is the critical constant）, the vortex-antivortex pairs are found.