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_:N2a92b3d5335045a38b30d96306d35591 "1" .
"On the collective properties of a boson system" .
"Physical Sciences" .
_:Na9b07b22d0c6434a94c1e3d46ded0d62 .
_:N751ac82d3d89405d9865b3f0802ccf06 .
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"research_article" .
"Valatin" .
"1958-10-01" .
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_:N32c60e852b7f42999d0d9b2209b7764a .
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_:Ncf6ef06ec1c14590a757a88dcfa1f80d "D." .
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_:Nda1ae0001bd54d0a83b4528e6b0db394 .
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"37-54" .
"1827-6121" .
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_:Nda1ae0001bd54d0a83b4528e6b0db394 "Department of Mathematical Physics, University of Birmingham, Birmingham" .
"2019-04-11T13:55" .
.
.
_:N751ac82d3d89405d9865b3f0802ccf06 "10" .
_:N32c60e852b7f42999d0d9b2209b7764a .
.
.
_:Nb09950ab45634681999b6df1c2d46abd "Department of Mathematical Physics, University of Birmingham, Birmingham" .
.
_:Na931b0822ef64e37babaf1bf95caf1af .
"A method in close correspondence with the theory of super-conductivity of Bardeen, Cooper and Schrieffer is applied to a boson system, extending an earlier approach byBogolubov. Minimizing the energy with respect to a trial ground state vector of exponential form, new equations and expressions are derived for the excitation spectrum of bosons. The expressions are in a one to one correspondence with those for fermions, from which formally they differ only through signs. The physical content of the expressions is, however, very different. Equations with a predominantly repulsive interaction which in the fermion case have no collective solutions, lead to such solutions for bosons because of a partial Bose-Einstein condensation. It is pointed out that the method is related to a linearization of the quantized matter field equations. Temperature dependent equations are obtained by the same methods as in the theory of superconductivity. The \u03BB-point is defined by the disappearance of the partial Bose-Einstein condensation." .
.
_:Ncf6ef06ec1c14590a757a88dcfa1f80d "Butler" .
"J. G." .
_:N2a92b3d5335045a38b30d96306d35591 .
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_:Nda1ae0001bd54d0a83b4528e6b0db394 .
_:Nf1bc74c3908a4edc9f5dca48aa850339 "Springer Nature - SN SciGraph project" .
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"Il Nuovo Cimento (1955-1965)" .
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_:Nf1bc74c3908a4edc9f5dca48aa850339 .
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"http://link.springer.com/10.1007/BF02859603" .
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_:N5db45dddc6664a95aa122c5debf5c708 .
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_:N5db45dddc6664a95aa122c5debf5c708 _:Ncf6ef06ec1c14590a757a88dcfa1f80d .
_:Na931b0822ef64e37babaf1bf95caf1af "pub.1022925082" .
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_:N2a92b3d5335045a38b30d96306d35591 .
"articles" .
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"1958-10" .
_:N34c05f4141064333b8a6ace32938c677 "10.1007/bf02859603" .
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_:Na9b07b22d0c6434a94c1e3d46ded0d62 .
_:N34c05f4141064333b8a6ace32938c677 "doi" .
_:N32c60e852b7f42999d0d9b2209b7764a "6d38425c792bbd4b6fa39d98f4895c76305cd8a1d407c18f8ced4c6dac3ca604" .
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"https://scigraph.springernature.com/explorer/license/" .
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"en" .
"Atomic, Molecular, Nuclear, Particle and Plasma Physics" .
_:Nf1bc74c3908a4edc9f5dca48aa850339 .