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Title: MOMENT OF INERTIA OF SUPERFLUID MANY-FERMION SYSTEMS

Abstract

The effects of possible superfluidity on the cranking moment of a lange many-fermion system moving under pericdic boundary conditions were investigated within the framework of the theory of superconductivity recently formulated by Bogolyubov. The Hamiltonian was initially subjected to Bogolyubov' s general unitary transformation. The coliective excitations of the fermions were then considered in the usual pnir approximation; the appropriate cranking terms were linear in the boson pair operators. On performing a unitary transformation which transformed away these linear terms, an expression was obtained for the momert of inertia of the system which included both the effects of pcssible superfluidity and collective excitation. This expression, by virtue of its being stationary with respect to arbitrary variations in the amplitude associated with the latter unitary transformation, was then utilized as a variational principle for the moment of inertia. The result previousiy obtained that the moment of inertia had a rigid value, was rederived in more compact form. For the superfluid state, it was found that collective excitations effected a marked increase in the superfluid moment at intermediate coupling strengths although the resulting moment was still quite small compared to the rigid value. In contrast to the normal state case, where particle-holemore » pairs play a major role, this increase was almost entirely due to excitations consisting of particle-pairs or hole-pairs. The precise magnitude of the apparent resonance in the moment produced by the d- wave part of the cranking interaction was dependent to some extent on the features of the particle-particle potential which led to the superffuid state. Variational expressions for the moment were exhibited for both Yukawa and deltafunction shell potentials. These results were identical in charged and neutral Fermi systems. A calculation of the cranking moment at finite temperatures was presented in an Appendix along with an interpretation of it in terms of Bardeen's two-fluid model of superconductivity. (auth)« less

Authors:
Publication Date:
Research Org.:
Brookhaven National Lab., Upton, N.Y.
OSTI Identifier:
4173559
NSA Number:
NSA-14-018383
Resource Type:
Journal Article
Journal Name:
Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D
Additional Journal Information:
Journal Volume: Vol: 118; Other Information: Orig. Receipt Date: 31-DEC-60
Country of Publication:
Country unknown/Code not available
Language:
English
Subject:
PHYSICS; BOSONS; COUPLING; EXCITATION; FERMIONS; INTERACTIONS; LOW TEMPERATURE; MANY BODY PROBLEM; MOTION; PERTURBATION THEORY; QUANTUM MECHANICS; RESONANCE; STATISTICS; SUPERFLUIDITY; VISCOSITY

Citation Formats

Rockmore, R M. MOMENT OF INERTIA OF SUPERFLUID MANY-FERMION SYSTEMS. Country unknown/Code not available: N. p., 1960. Web. doi:10.1103/PhysRev.118.1645.
Rockmore, R M. MOMENT OF INERTIA OF SUPERFLUID MANY-FERMION SYSTEMS. Country unknown/Code not available. https://doi.org/10.1103/PhysRev.118.1645
Rockmore, R M. 1960. "MOMENT OF INERTIA OF SUPERFLUID MANY-FERMION SYSTEMS". Country unknown/Code not available. https://doi.org/10.1103/PhysRev.118.1645.
@article{osti_4173559,
title = {MOMENT OF INERTIA OF SUPERFLUID MANY-FERMION SYSTEMS},
author = {Rockmore, R M},
abstractNote = {The effects of possible superfluidity on the cranking moment of a lange many-fermion system moving under pericdic boundary conditions were investigated within the framework of the theory of superconductivity recently formulated by Bogolyubov. The Hamiltonian was initially subjected to Bogolyubov' s general unitary transformation. The coliective excitations of the fermions were then considered in the usual pnir approximation; the appropriate cranking terms were linear in the boson pair operators. On performing a unitary transformation which transformed away these linear terms, an expression was obtained for the momert of inertia of the system which included both the effects of pcssible superfluidity and collective excitation. This expression, by virtue of its being stationary with respect to arbitrary variations in the amplitude associated with the latter unitary transformation, was then utilized as a variational principle for the moment of inertia. The result previousiy obtained that the moment of inertia had a rigid value, was rederived in more compact form. For the superfluid state, it was found that collective excitations effected a marked increase in the superfluid moment at intermediate coupling strengths although the resulting moment was still quite small compared to the rigid value. In contrast to the normal state case, where particle-hole pairs play a major role, this increase was almost entirely due to excitations consisting of particle-pairs or hole-pairs. The precise magnitude of the apparent resonance in the moment produced by the d- wave part of the cranking interaction was dependent to some extent on the features of the particle-particle potential which led to the superffuid state. Variational expressions for the moment were exhibited for both Yukawa and deltafunction shell potentials. These results were identical in charged and neutral Fermi systems. A calculation of the cranking moment at finite temperatures was presented in an Appendix along with an interpretation of it in terms of Bardeen's two-fluid model of superconductivity. (auth)},
doi = {10.1103/PhysRev.118.1645},
url = {https://www.osti.gov/biblio/4173559}, journal = {Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D},
number = ,
volume = Vol: 118,
place = {Country unknown/Code not available},
year = {1960},
month = {6}
}