Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 45: Magnetic Coupling and Spin Structures
MA 45.10: Vortrag
Donnerstag, 14. März 2013, 17:30–17:45, H10
The phase diagram of the quantum spin-2 XXZ chain with on-site anisotropy — •Jonas A. Kjäll1,2, Michael P. Zaletel1, Roger S. K. Mong1,3, Jens H. Bardarson1,4, and Frank Pollmann2 — 1Department of Physics, University of California, Berkeley, California 94720, USA — 2Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden, Germany — 3Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA — 4Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
How the highly quantum mechanical phase diagrams at small spin is connected with the classical (infinite spin) phase diagrams is interesting for many models. We focus on a particular problem, the ground state phase diagram of the quantum spin-2 XXZ chain in the presence of on- site anisotropy. We use a state of the art infinite system density-matrix-renormalization- group (iDMRG) algorithm and show how many challenging phases and phase transitions in quantum spin systems can be accurately detected. Different types of on-site anisotropies are considered, allowing us to establish the validity of the following statements: One, the spin-2 model can be tuned into a phase which is equivalent to the "topologically nontrivial" spin-1 Haldane phase. Two, the spin-2 Haldane phase at the isotropic Heisenberg point is adiabatically connected to the "trivial" large-D phase, with a continuous change of the Hamiltonian parameters. Furthermore, we study the spin-3 XXZ chain to help explain the development of the classical phase diagram.