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Collective Action Formalism on the Keldysh Contour for Disordered and Hubbard‐Correlated Electrons
Author(s) -
Kolley E.,
Kolley W.
Publication year - 1988
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221450224
Subject(s) - hubbard model , effective action , saddle point , saddle , physics , methods of contour integration , gaussian , formalism (music) , electron , action (physics) , mathematical physics , quantum mechanics , quantum electrodynamics , statistical physics , mathematics , mathematical analysis , geometry , art , mathematical optimization , musical , visual arts , superconductivity
A real‐time finite‐temperature field theory on the Keldysh contour is used to describe the dynamics of an electron system within a random Hubbard model. The effective, i.e. quenched‐averaged, fermionic action under the functional integral is bosonized by introducing both a matrix field and an exchange field via Hubbard‐Stratonovich transformations. The resulting collective action permits the loop expansion, giving rise to a systematic approximation scheme. The saddle point and Gaussian fluctuations around it are calculated.