DYNAMICAL SUSCEPTIBILITIES IN THE STRONG COUPLING APPROACH: A GENERAL SCHEME AND THE FALICOV--KIMBALL MODEL

A. M. Shvaika

Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine
1 Svientsitskii Str., Lviv, UA--79011, Ukraine

A general scheme to calculate dynamical susceptibilities of strongly correlated electron systems within the dynamical mean field theory is developed. The approach is based on an expansion over electron hopping around the atomic limit (within the diagrammatic technique for site operators: projection and Hubbard ones) in infinite dimensions. As an example, the Falicov-Kimball and simplified pseudospin-electron models are considered for which an analytical expressions for dynamical susceptibilities are obtained.

PACS number(s): 75.40.Gb, 71.10.Fd, 71.27.+a

ps