1999/03/04 by J. L. Smith, J. Lleweilun Smith, Qimiao Si · 10 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.61.5184
28 pages, REVTEX, 8 figures included
arxiv created 1999/03/04 · openalex publication_date 2000/02/15 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We further develop an extended dynamical mean-field approach introduced earlier. It goes beyond the standard D=\ensuremath∞ dynamical mean field theory by incorporating quantum fluctuations associated with intersite (Ruderman-Kittel-Kasuya-Yosida like) interactions. This is achieved by scaling the intersite interactions to the same power in 1/D as that for the kinetic terms. In this approach, a correlated lattice problem is reduced to a single-impurity Anderson model with additional self-consistent bosonic baths. Here, we formulate the approach in terms of standard perturbation expansions. We show that the two-particle vertex functions are momentum-dependent, while the single-particle self-energy remains local. In spite of this, the approach is conserving. Finally, we also determine the form of a momentum-dependent dynamical susceptibility; the resulting expression relates it to the corresponding Weiss field, local correlation function and (momentum-dependent) intersite coupling.