Berlin 2005 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DY: Dynamik und Statistische Physik
DY 50: Critical Phenomena and Phase Transitions
DY 50.1: Hauptvortrag
Mittwoch, 9. März 2005, 09:45–10:15, TU H3010
Integrable sl(2/1) super spin chain and the spin quantum Hall effect — •Holger Frahm1, Fabian H. L. Essler2, and Hubert Saleur3,4 — 1Institut für Theoretische Physik, Universität Hannover — 2Theoretical Physics, Oxford University — 3Service de Physique Théorique, CEA Saclay — 4Dept. of Physics and Astronomy, University of Southern California
The analysis of network models – either directly or by numerical studies of related quantum spin chains with super group symmetry – allows to gain insights into the delocalisation transition of non-interacting two-dimensional electrons with disorder. Critical exponents determined this way are an important step towards the identification of the conformal field theory (CFT) describing the universal physics at the transition. To collect more information on the universal properties of the “spin quantum Hall” transition which may occur in disordered superconductors with certain restrictions on the symmetry an integrable version of the corresponding super spin chain has been proposed [1]. Analyzing the ground state and some low-lying excitations of this integrable chain we determine the central charge of the underlying CFT and obtain evidence for an infinite degeneracy of the finite size gaps (possibly related to a continuous sectrum of the CFT). Finally, we compare our findings for the integrable chain with known properties of the (non-integrable) network model for the spin QHE.
[1] R. M. Gade, J. Phys. A32 (1999) 7071