Topological Quantum Numbers in Nonrelativistic Physics
Topological Quantum Numbers in Nonrelativistic Physics
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DOI：
10.1142/s0217979297001623
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发表时间：
1998-03
期刊：
影响因子：
--
通讯作者：
D. Thouless
中科院分区：
文献类型：
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作者：
D. Thouless
尽管对设备细节的控制相对较差，但使用交流约瑟夫森效应的电压测量和使用量子霍尔效应的电阻测量能够达到非常高的精度。这种测量依赖于拓扑量子数，与基于对称性的量子数不同，拓扑量子数对系统与理想状态的偏差不敏感。超流体 4He 中的循环、超导体中的通量量子化和量子化霍尔电导都是拓扑量子数的例子，但只有最后两个已知是非常精确的。维宁对量子环流的早期测量是基于对由此产生的马格努斯力的测量，而我们（平敖、黔牛和我）最近证明，马格努斯力的强度本身可以由与拓扑论证具有共同特征的论证来确定。
Voltage measurements using the ac Josephson effect and electrical resistance measurements using the quantum Hall effect are capable of very high precision, despite the relatively poor control of details of the devices. Such measurements rely on topological quantum numbers, which, unlike symmetry-based quantum numbers, are insensitive to deviations of the system from ideality. The circulation in superfluid 4He, flux quantization in superconductors and quantized Hall conductance are all examples of topological quantum numbers, but only the last two are known to be very precise. Vinen's early measurement of quantized circulation was based on measurement of the resulting Magnus force, and we (Ping Ao, Qian Niu and I) have recently shown that the strength of the Magnus force can itself be determined by an argument that shares common features with topological arguments.