Department of Engineering Science, University of Electro-Communications, Tokyo 182-8585, Japan.
J Phys Condens Matter. 2013 Oct 9;25(40):404212. doi: 10.1088/0953-8984/25/40/404212. Epub 2013 Sep 11.
Spontaneous spin vortex formation in a magnetic phase transition of a trapped spin-1 Bose-Einstein condensate is investigated based on mean-field theory. In a harmonic trapping potential, an inhomogeneous atomic density leads to spatial variations of the critical point, magnetization time, and spin correlation length. The Kibble-Zurek phenomena are shown to emerge even in such inhomogeneous spinor condensates, when the quench of the quadratic Zeeman energy is fast enough. For slow quench, the magnetized region gradually expands from the center of the trap, pushing out spin vortices, which hinders the Kibble-Zurek mechanism from occurring. The case of a toroidal trapping potential is also discussed.
基于平均场理论，研究了囚禁自旋-1 玻色-爱因斯坦凝聚体的磁相变中自发自旋涡旋的形成。在谐波陷阱中，不均匀的原子密度导致临界点、磁化时间和自旋关联长度的空间变化。即使在这种不均匀的旋量凝聚体中，当二次塞曼能的猝灭足够快时，也会出现 Kibble-Zurek 现象。对于缓慢的猝灭，磁化区域逐渐从阱的中心扩展，推出自旋涡旋，这阻碍了 Kibble-Zurek 机制的发生。还讨论了环形陷阱的情况。
