Nonlinear Dynamical Systems Group, Computational Science Research Center, and Department of Mathematics and Statistics, San Diego State University, San Diego, California 92182-7720, USA.
Phys Rev Lett. 2013 May 31;110(22):225301. doi: 10.1103/PhysRevLett.110.225301. Epub 2013 May 28.
We study the dynamics of small vortex clusters with a few (2-4) corotating vortices in Bose-Einstein condensates by means of experiments, numerical computations, and theoretical analysis. All of these approaches corroborate the counterintuitive presence of a dynamical instability of symmetric vortex configurations. The instability arises as a pitchfork bifurcation at sufficiently large values of the vortex system angular momentum that induces the emergence and stabilization of asymmetric rotating vortex configurations. The latter are quantified in the theoretical model and observed in the experiments. The dynamics is explored both for the integrable two-vortex particle system, where a reduction of the phase space of the system provides valuable insight, as well as for the nonintegrable three- (or more) vortex case, which additionally admits the possibility of chaotic trajectories.
我们通过实验、数值计算和理论分析研究了玻色-爱因斯坦凝聚体中具有少数（2-4）个同向涡旋的小涡旋簇的动力学。所有这些方法都证实了对称涡旋构型存在动态不稳定性这一违背直觉的现象。这种不稳定性是在涡旋系统角动量足够大时作为叉形分岔出现的，它导致了非对称旋转涡旋构型的出现和稳定。在后一种情况下，理论模型进行了量化，实验中也进行了观察。我们探索了可积的双涡旋粒子系统的动力学，其中系统相空间的简化提供了有价值的见解，以及不可积的三（或更多）涡旋情况，它还允许存在混沌轨迹。
