In:
International Journal of Modern Physics B, World Scientific Pub Co Pte Ltd, Vol. 05, No. 06n07 ( 1991-04), p. 885-905
Abstract:
We review the slave-boson representations of the Hubbard model. When both spin and charge fermion degrees of freedom are represented by Bose fields, the approach is equivalent at the "self-consistent" saddle point level to the Gutzwiller approximation (GA). We show how the determination of the Lagrange multipliers, introduced to enforce the constraints, involves a Mott-Hubbard gap near half-filling for U 〉 U c (localization edge). The quantum fluctuations are then considered within a renormalized basis of boson fields (restoring the spin-rotation invariance), which brings out two distinct channels, symmetric and antisymmetric. It is remarkable that both spin and charge fluctuations are obtained at the same level of the gaussian fluctuations, as oppossed to the standard 1/N expansion. This provides the microscopic basis for a Fermi liquid theory. Both dynamic effects and extension to finite temperature which were beyond the scope of the variational procedure can now be described by this approach. The physical implications of the model (dynamic correlation functions, T 3 Ln T term of the specific heat, superfluid instability) are finally considered, all of which reflect the Fermi liquid nature of the system.
Type of Medium:
Online Resource
ISSN:
0217-9792
,
1793-6578
DOI:
10.1142/S021797929100047X
Language:
English
Publisher:
World Scientific Pub Co Pte Ltd
Publication Date:
1991
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