TITLE:
Variational Principle in the Quantum Statistical Theory
AUTHORS:
Eduard A. Arinshteyn
KEYWORDS:
Generating Functional, Density Matrices, Correlations, Irreducible Part, Variational Method
JOURNAL NAME:
Journal of Modern Physics,
Vol.5 No.14,
August
22,
2014
ABSTRACT: In the
present paper, a generalization of the method of partial summation of the
expansion of the thermodynamical potential is proposed. This generalization
allows one to obtain the corresponding equations for higher-order correlation
matrices, as well as to formulate the variational method for their solution. We
show that correlation matrices of equilibrium quantum system satisfy a
variational principle for thermodynamic potential which is functional of these
matrices that provides a thermodynamic consistency of the theory. This result
is similar to a variational principle for correlation functions of classical
systems.