A new type of half-quantum circulation in a macroscopic polariton spinor ring condensate
A new type of half-quantum circulation in a macroscopic polariton spinor ring condensate
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DOI：
10.1073/pnas.1424549112
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发表时间：
2015-03-03
影响因子：
11.1
通讯作者：
West, Ken
中科院分区：
文献类型：
--
作者：
Liu, Gangqiang;Snoke, David W.;West, Ken
本文报道了环几何中宏观玻色-爱因斯坦极化子凝聚体中相干循环的观测。因为它们是自旋凝聚体，所以半量子是允许存在的，其中有一个相位旋转的pi与一个偏振矢量旋转的p围绕一个闭合路径。这种半量子行为在环周围偏振旋转的实验观察中可以清楚地看到。在我们的环几何中，我们看到的半量子态是自旋的手性从环的一边翻转到另一边除了线性偏振分量的旋转；这种状态在环形几何中是允许的，但在单连通几何中不会发生。这种状态比自旋方向不变的半量子态能量低，对应于两种不同的基本半量子态的叠加。环内流动的循环方向在顺时针和逆时针之间随机波动；这种涨落对应于系统中时间反转对称性的自发破缺。这种类型的宏观极化环凝聚使得直接控制循环激发高量子化态和创建约瑟夫森结隧道势垒成为可能。
We report the observation of coherent circulation in a macroscopic Bose-Einstein condensate of polaritons in a ring geometry. Because they are spinor condensates, half-quanta are allowed in where there is a phase rotation of pi in connection with a polarization vector rotation of p around a closed path. This half-quantum behavior is clearly seen in the experimental observations of the polarization rotation around the ring. In our ring geometry, the half-quantum state that we see is one in which the handedness of the spin flips from one side of the ring to the other side in addition to the rotation of the linear polarization component; such a state is allowed in a ring geometry but will not occur in a simply connected geometry. This state is lower in energy than a half-quantum state with no change of the spin direction and corresponds to a superposition of two different elementary half-quantum states. The direction of circulation of the flow around the ring fluctuates randomly between clockwise and counterclockwise from one shot to the next; this fluctuation corresponds to spontaneous breaking of time-reversal symmetry in the system. This type of macroscopic polariton ring condensate allows for the possibility of direct control of the circulation to excite higher quantized states and the creation of Josephson junction tunneling barriers.