Effective-action approach to strongly correlated fermion systems
Abstract
We construct a functional for the single-particle Green's function, which is a variant of the standard Baym-Kadanoff functional. The stability of the stationary solutions to the functional is directly related to aspects of the irreducible particle hole interaction through the Bethe-Salpeter equation. A startling aspect of this functional is that it allows a simple and rigorous derivation of both the standard and extended dynamical mean-field (DMFT) equations as stationary conditions. Though the DMFT equations were formerly obtained only in the limit of infinite lattice coordination, the functional described in the work presents a way of directly extending DMFT to finite-dimensional systems, both on a lattice and in a continuum. Instabilities of the stationary solution at the bifurcation point of the functional signal the appearance of a zero mode at the Mott transition which then couples to physical quantities resulting in divergences at the transition.
- Publication:
-
Physical Review B
- Pub Date:
- March 2001
- DOI:
- 10.1103/PhysRevB.63.115110
- arXiv:
- arXiv:cond-mat/9911223
- Bibcode:
- 2001PhRvB..63k5110C
- Keywords:
-
- 71.27.+a;
- Strongly correlated electron systems;
- heavy fermions;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 9 pages