title: Ground-state approximation for strongly interacting spin systems in arbitrary spatial dimension.
abstract: We introduce a variational method for the approximation of ground states of strongly interacting spin systems in arbitrary geometries and spatial dimensions. The approach is based on weighted graph states and superpositions thereof. These states allow for the efficient computation of all local observables (e.g., energy) and include states with diverging correlation length and unbounded multiparticle entanglement. As a demonstration, we apply our approach to the Ising model on 1D, 2D, and 3D square lattices. We also present generalizations to higher spins and continuous-variable systems, which allows for the investigation of lattice field theories.
authors.affiliation: Institut für Theoretische Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Anders
authors.forename: M B
authors.initials: MB
authors.lastname: Plenio
authors.forename: W
authors.initials: W
authors.lastname: Dür
authors.forename: F
authors.initials: F
authors.lastname: Verstraete
authors.forename: H-J
authors.initials: HJ
authors.lastname: Briegel