超导体中库珀对的SU(2)与Glauber相干态——库珀对与约瑟夫森超流性的量子特性研究  

SU(2) AND GLAUBER COHERENT STATES OF COOPER PAIRS IN SUPERCONDUCTOR——STUDIES OF THE QUANTUM CHARACTERS OF COOPER PAIRS AND JOSEPHSON SUPERFLUIDITY

作　　者：黄洪斌[1] 

机构地区：[1]东南大学物理系,南京210018

出　　处：《物理学报》1991年第9期1402-1410,共9页Acta Physica Sinica

摘　　要：本文利用类自旋算符证明BCS超导基态波函数是单个库珀对SU(2)相干态波函数的直积、且在一定条件下为库珀对体系的SU(2)相干态波函数。若两块处在BCS超导基态的超导体耦合在一起,则体系仍处在SU(2)相干态,且在一定条件下为定态超辐射态。在SU(2)群到谐振子群的收缩下,库珀对的SU(2 )相干态变为Glauber相干态。讨论了两种情形下库珀对与约瑟夫森超流性的量子噪声、分布及二阶相关特性。It is shown, using the quasi-spin operator, that the BCS superconducting ground-state wave function is the direct product of single Cooper-pair SU(2) coherent state wave functions, and in certain conditions, is SU(2) coherent state wave function of the Cooper-pair system. If two superconductors, both in BCS ground state, are coupled together, the coupled system is also in SU(2) coherent state. Under the contraction of group SU(2) to harmonic-oscillator group, the SU(2) coherent states contract to Glauber coherent states. The quantum fluctuations, distributions, and second correlations of Cooper pairs and Josephson superfluidity in the two cases are discussed.

关 键 词：超导体 库珀对 SU(2) 相干态 

分 类 号：O512[理学—低温物理]