TY - JOUR
T1 - The superfluid phases of liquid 3He
T2 - BCS theory
AU - Leggett, A. J.
N1 - Funding Information:
This work was partially supported by the National Science Foundation under Grant No. NSF DMR09-06921.
PY - 2010/10/10
Y1 - 2010/10/10
N2 - Following the success of the original BCS theory as applied to superconductivity in metals, it was suggested that the phenomenon of Cooper pairing might also occur in liquid 3-He, though unlike the metallic case the pairs would most likely form in an anisotropic state, and would then lead in this neutral system to superfluidity. However, what had not been anticipated was the richness of the phenomena which would be revealed by the experiments of 1972. In the first place, even in a zero magnetic field there is not one but two superfluid phases, and the explanation of this involves ideas concerning "spin fluctuation feedback" which have no obvious analog in metals. Secondly, the anisotropic nature of the pair wave function, which in the case of the B phase is quite subtle, and the fact that the orientation must be the same for all the pairs, leads to a number of qualitatively new effects, in particular to a spectacular amplification of ultra-weak interactions seen most dramatically in the NMR behavior. In this chapter I review the application of BCS theory to superfluid 3-He with emphasis on these novel features.
AB - Following the success of the original BCS theory as applied to superconductivity in metals, it was suggested that the phenomenon of Cooper pairing might also occur in liquid 3-He, though unlike the metallic case the pairs would most likely form in an anisotropic state, and would then lead in this neutral system to superfluidity. However, what had not been anticipated was the richness of the phenomena which would be revealed by the experiments of 1972. In the first place, even in a zero magnetic field there is not one but two superfluid phases, and the explanation of this involves ideas concerning "spin fluctuation feedback" which have no obvious analog in metals. Secondly, the anisotropic nature of the pair wave function, which in the case of the B phase is quite subtle, and the fact that the orientation must be the same for all the pairs, leads to a number of qualitatively new effects, in particular to a spectacular amplification of ultra-weak interactions seen most dramatically in the NMR behavior. In this chapter I review the application of BCS theory to superfluid 3-He with emphasis on these novel features.
KW - anisotropy
KW - Cooper pairs
KW - NMR
KW - spin fluctuation feedback
KW - superfluid amplification
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U2 - 10.1142/S0217984910025103
DO - 10.1142/S0217984910025103
M3 - Article
AN - SCOPUS:77956909905
SN - 0217-9849
VL - 24
SP - 2525
EP - 2539
JO - Modern Physics Letters B
JF - Modern Physics Letters B
IS - 25
ER -