Condensed Matter Physics, 2006, vol. 9, No. 3(47), p. 587602, English
DOI:10.5488/CMP.9.3.587
Title:
Asymmetric Hubbard model within generating functional approach in dynamical mean field theory
Author(s):
 I.V.Stasyuk
(Institute for Condensed Matter Physics of the
National Academy of Sciences of Ukraine, 1 Svientsitskii Str.,
79011 Lviv, Ukraine)
,

 O.B.Hera
(Institute for Condensed Matter Physics of the
National Academy of Sciences of Ukraine, 1 Svientsitskii Str.,
79011 Lviv, Ukraine)

In the paper a new analytic approach to the solution of the
effective singlesite problem in the dynamical mean field theory
is developed. The approach is based on the method of the
KadanoffBaym generating functional in the form developed by
Izyumov et al. It makes it possible to obtain a closed equation in
functional derivatives for the irreducible part of the singlesite
particle Green's function; the solution is constructed
iteratively. As an application of the proposed approach the
asymmetric Hubbard model (AHM) is considered. The inverse
irreducible part Ξ^{1}_{σ} of the singlesite Green's
function is constructed in the linear approximation with respect
to the coherent potential J_{σ}. Basing on the obtained
result, the Green's function of itinerant particles in the
FalicovKimball limit of AHM is considered, and the decoupling
schemes in the equations of motion approach (GH3 approximation,
decoupling by Jeschke and Kotliar) are analysed.
Key words:
strongly correlated systems, asymmetric Hubbard model,
singlesite problem, dynamical mean field theory
PACS:
71.10.Fd, 71.27.+a, 71.30.+h
