Spin domains in ground-state Bose-Einstein condensates
Spin domains in ground-state Bose-Einstein condensates
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DOI：
10.1038/24567
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发表时间：
1998-11-26
期刊：
影响因子：
64.8
通讯作者：
Ketterle, W
中科院分区：
文献类型：
--
作者：
Stenger, J;Inouye, S;Ketterle, W
玻色-爱因斯坦凝聚体--一种低温形式的物质，其中宏观玻色子占据量子力学基态--已经在弱相互作用的碱金属（1-3）和氢（25）原子的稀气体中得到证实。磁阱通常被用来限制凝聚态，但其缺点是原子的自旋翻转会导致未被捕获的态。因此，不能将被俘获的碱金属原子的自旋取向视为自由度。因此，这种凝聚体可以用标量序参量来描述，就像无自旋的超流体He-4一样。相比之下，最近实现的钠凝聚物的光学陷阱（4）限制原子独立于它们的自旋方向。这提供了研究“旋量”凝聚体的可能性，其中自旋包括一个自由度，因此序参数是一个矢量，而不是标量。本文报道了钠旋量凝聚在光阱中的平衡态的观测结果。自旋取向的自由度导致在外部磁场中形成自旋畴，其可以彼此混溶或不混溶。
Bose-Einstein condensates-a low-temperature form of matter in which a macroscopic population of bosons occupies the quantum-mechanical ground state-have been demonstrated for weakly interacting dilute gases of alkali-metal(1-3) and hydrogen(25) atoms. Magnetic traps are usually employed to confine the condensates, but have the drawback that spin flips in the atoms lead to untrapped states. For this reason, the spin orientation of the trapped alkali atoms cannot be regarded as a degree of freedom. Such condensates are therefore described by a scalar order parameter, like the spinless superfluid He-4. In contrast, a recently realized optical trap(4) for sodium condensates confines atoms independently of their spin orientations. This offers the possibility of studying 'spinor' condensates in which spin comprises a degree of freedom, so that the order parameter is a vector rather than scalar quantity. Here we report the observation of equilibrium states of sodium spinor condensates in an optical trap. The freedom of spin orientation leads to the formation of spin domains in an external magnetic field, which can be either miscible or immiscible with one another.