Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 25: Correlated Electrons: Low-Dimensional Systems - Models 3
TT 25.13: Vortrag
Dienstag, 12. März 2013, 13:00–13:15, H9
Quantum state renormalization group approach to symmetry-protected topological phases — •Ching-Yu Huang1, Frank Pollmann1, Feng-Li Lin2, and Xie Chen3 — 1MPIPKS, Dresden,Germany — 2NTNU, Taipei, Taiwan — 3UC Berkeley,Berkeley, USA
Topologically phases do not break symmetries and can thus not be characterized by local order parameters. A particular kind of topological phases are the so-called symmetry-protected topological phases (SPTP) which are only distinct from a trivial phase as long as certain symmetries are preserved. The first example of a SPTP is the Haldane phase in S=1 spin chains. We use a symmetry preserving quantum state renormalization group (QSRG) method to characterize SPTP. The QSRG removes short range entanglement and yields a fixed point state which is then used to characterize the phase. For this, we first apply the infinite time-evolving block decimation (iTEBD) method to numerically find the ground state wave function which is then used as initial state for the QSRG procedure. As a simple example we study the one-dimensional Haldane phase. We then extend the method to two dimensions, and study the SU(2) symmetric, two-dimensional quantum spin-3/2 systems on the honeycomb lattice as well as a recently introduced model which realizes a SPTP.