Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 22: CE: Spin Systems and Itinerant Magnets
TT 22.2: Vortrag
Mittwoch, 24. März 2010, 09:45–10:00, H21
Non-abelian statistics in higher spin antiferromagnets — Burkhard Scharfenberger1, Ronny Thomale2, and •Martin Greiter1 — 1Institut für Theorie der Kondensierten Materie, KIT, 76128 Karlsruhe — 2Department of Physics, Princeton University, Princeton, NJ 08544, USA
We conjecture, and provide some preliminary evidence, that spinons (and holons) in antiferromagnets with spin S=2 and higher generally obey non-abelian statistics (SU(2) level k=2S anyons for S integer). The line of argument is as follows. In one dimension, a paradigm for a general S=1 spin chain (the AKLT chain) can be obtained by projecting two dimer (or Majumdar-Ghosh) chains with S=1/2 together. Similarly, we can obtain an S=1 spin liquid from projecting two S=1/2 chiral spin liquids together [M.Greiter, J.Low Temp. Phys. 126, 1029 (2002)]. In both cases, a discrete symmetry is violated for the S=1/2 models, which is restored for S=1. We assume that the S=1 spin liquid provides a paradigm of the disorderd S=1 antiferromagnet. If this is correct, we may further assume that an S=2 spin liquid generated by projecting two of these S=1 liquids together will in turn provide a paradigm of the disordered S=2 antiferromagnet. We provide evidence that the excitations of this S=2 spin liquid obey non-abelian statistics, and show that the degeneracy on a torus is 3× 3=9, as expected for two species of Ising (SU(2) level k=1) anyons with opposite chiralities.