Mukerjee Subroto, Xu Cenke, Moore J E
Department of Physics, University of California, Berkeley, CA 94720, USA.
Phys Rev Lett. 2006 Sep 22;97(12):120406. doi: 10.1103/PhysRevLett.97.120406. Epub 2006 Sep 20.
The s=1 spinor Bose condensate at zero temperature supports ferromagnetic and polar phases that combine magnetic and superfluid ordering. We analyze the topological defects of the polar condensate, correcting previous studies, and show that the polar condensate in two dimensions is unstable at any finite temperature; instead, there is a nematic or paired superfluid phase with algebraic order in exp(2itheta), where theta is the superfluid phase, and no magnetic order. The Kosterlitz-Thouless transition out of this phase is driven by unbinding of half-vortices (the spin-disordered version of the combined spin and phase defects found by Zhou), and the anomalous universal 8T(c)/pi stiffness jump at the transition is confirmed in numerical simulations. The anomalous stiffness jump is a clear experimental signature of this phase and the corresponding phase transition.
零温度下的自旋为1的玻色凝聚体支持结合了磁序和超流序的铁磁相和极性相。我们分析了极性凝聚体的拓扑缺陷，纠正了先前的研究，并表明二维中的极性凝聚体在任何有限温度下都是不稳定的；相反，存在一种向列相或配对超流相，其具有(exp(2i\theta))形式的代数序，其中(\theta)为超流相，且不存在磁序。从该相的Kosterlitz-Thouless转变是由半涡旋的解束缚驱动的（半涡旋是Zhou发现的自旋和相位缺陷的自旋无序版本），并且在数值模拟中证实了转变处反常的通用(8T(c)/\pi)刚度跃变。反常的刚度跃变是该相和相应相变的一个明确的实验特征。
