title: Density matrix embedding: a simple alternative to dynamical mean-field theory.
abstract: We introduce density matrix embedding theory (DMET), a quantum embedding theory for computing frequency-independent quantities, such as ground-state properties, of infinite systems. Like dynamical mean-field theory, DMET maps the bulk interacting system to a simpler impurity model and is exact in the noninteracting and atomic limits. Unlike dynamical mean-field theory, DMET is formulated in terms of the frequency-independent local density matrix, rather than the local Green's function. In addition, it features a finite, algebraically constructible bath of only one bath site per impurity site, with no bath discretization error. Frequency independence and the minimal bath make DMET a computationally simple and efficient method. We test the theory in the one-dimensional and two-dimensional Hubbard models at and away from half filling, and we find that compared to benchmark data, total energies, correlation functions, and metal-insulator transitions are well reproduced, at a tiny computational cost.
authors.affiliation: Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Gerald
authors.initials: G
authors.lastname: Knizia
authors.forename: Garnet Kin-Lic
authors.initials: GK
authors.lastname: Chan