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Expansion of Free Energy in Terms of Correlation Functions Within the Landau‐Ginzburg Model I. Fundamental Relations
Author(s) -
Madzhulis I.,
Kaupužs J.
Publication year - 1993
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.2221750202
Subject(s) - statistical physics , correlation function (quantum field theory) , energy (signal processing) , function (biology) , energy functional , correlation , correlation integral , mathematics , landau theory , ginzburg–landau theory , physics , phase transition , mathematical analysis , quantum mechanics , superconductivity , geometry , evolutionary biology , dielectric , biology
The free energy can be expanded in terms of correlation functions on the basis of the Landau‐Ginzburg phase transition model for ferroelectrics. An equation for the two‐point correlation function is obtained from the extremum condition of the free energy function. A new criterion is proposed to choose skeleton diagrams for the free energy with an account of fluctuations. Results obtained for any functional integral in statistical physics can be generalized.