Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 8: CE: (General) Theory
TT 8.14: Talk
Monday, March 22, 2010, 17:30–17:45, H21
Lattice Density Functional Theory of the inhomogeneous Hubbard model. — •Matthieu Saubanère and G. M. Pastor — Institut für Theoretische Physik, Universität Kassel, Kassel, Germany
The inhomogeneous Hubbard Hamiltonian is investigated in the framework of lattice density functional theory (LDFT). The single-particle density-matrix γij with respect to the lattice sites is considered as the basic variable of the many-body problem. Two new approximations to the interaction-energy functional W[γij] are proposed. The first one is based on the scaling properties of W[γij]. It allows to recover the exact limit of strong correlations for the homogeneous Hubbard Hamiltonian at half band-filling. The second one is obtained by projecting the many-body ground-state on the different states with defined occupations of the atomic sites. A system of equations is then derived, from which W[γij] is obtained. As examples of applications we present results for the kinetic, Coulomb and total ground-state energy, charge excitation gap, and charge susceptibility of the inhomogeneous Hubbard model in one, two and three dimensional periodic lattices, as well as in small clusters. The accuracy of the method is demonstrated by comparison with available analytical and numerical exact solutions.