Asymptotic exactness of c-number substitution in Bogolyubov's theory of superfluidity

The Bogolyubov model of liquid helium is considered. The validity of substituting a c-number for the k=0 mode operator â0 is established rigorously. The domain of stability of the Bogolyubov's Hamiltonian is found. We derive sufficient conditions which ensure the appearance of the Bose condensa...

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Published in:Condensed Matter Physics
Date:2010
Main Authors: Bogolyubov (jr), N.N., Sankovich, D.P.
Format: Article
Language:English
Published: Інститут фізики конденсованих систем НАН України 2010
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/32088
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:Asymptotic exactness of c-number substitution in Bogolyubov's theory of superfluidity / N.N. Bogolyubov, Jr., D.P. Sankovich // Condensed Matter Physics. — 2010. — Т. 13, № 2. — С. 23002: 1-6. — Бібліогр.: 14 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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Summary:The Bogolyubov model of liquid helium is considered. The validity of substituting a c-number for the k=0 mode operator â0 is established rigorously. The domain of stability of the Bogolyubov's Hamiltonian is found. We derive sufficient conditions which ensure the appearance of the Bose condensate in the model. For some temperatures and some positive values of the chemical potential, there is a gapless Bogolyubov spectrum of elementary excitations, leading to a proper microscopic interpretation of superfluidity.
ISSN:1607-324X