Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom.
Phys Rev Lett. 2010 Feb 5;104(5):050404. doi: 10.1103/PhysRevLett.104.050404.
We report the observation of vortex nucleation in a rotating optical lattice. A 87Rb Bose-Einstein condensate was loaded into a static two-dimensional lattice and the rotation frequency of the lattice was then increased from zero. We studied how vortex nucleation depended on optical lattice depth and rotation frequency. For deep lattices above the chemical potential of the condensate we observed a linear dependence of the number of vortices created with the rotation frequency, even below the thermodynamic critical frequency required for vortex nucleation. At these lattice depths the system formed an array of Josephson-coupled condensates. The effective magnetic field produced by rotation introduced characteristic relative phases between neighboring condensates, such that vortices were observed upon ramping down the lattice depth and recombining the condensates.
我们报告了在旋转光学晶格中涡旋核的观测。将 87Rb 玻色-爱因斯坦凝聚体装入静态二维晶格中，然后从零开始增加晶格的旋转频率。我们研究了涡旋核的形成如何取决于光学晶格深度和旋转频率。对于深晶格，超过凝聚体的化学势，我们观察到随着旋转频率的增加，形成的涡旋数量呈线性关系，即使低于涡旋核形成所需的热力学临界频率。在这些晶格深度下，系统形成了约瑟夫森耦合凝聚体的阵列。旋转产生的有效磁场在相邻凝聚体之间引入了特征的相对相位，从而在降低晶格深度并重新组合凝聚体时观察到涡旋。
