Critical exponents of random XX and XY chains: Exact results via random walks |
| |
Authors: | H Rieger R Juhász F Iglói |
| |
Institution: | FB 10.1 Theoretische Physik, Universit?t des Saarlandes, 66041, Saarbrücken, Germany Institute for Theoretical Physics,Szeged University, 6720, Szeged, Hungary Laboratoire de Physique des Matériaux, Université Henri Poincaré, B.P. 239, 54506, Vandoevre lès Nancy Cedex, France
|
| |
Abstract: | We study random XY and (dimerized) XX spin-1/2 quantum spin chains at their quantum phase transition driven by the anisotropy and dimerization, respectively. Using
exact expressions for magnetization, correlation functions and energy gap, obtained by the free fermion technique, the critical
and off-critical (Griffiths-McCoy) singularities are related to persistence properties of random walks. In this way we determine
exactly the decay exponents for surface and bulk transverse and longitudinal correlations, correlation length exponent and
dynamical exponent.
Received 26 September 1999 |
| |
Keywords: | PACS 75 50 Lk Spin glasses and other random magnets - 71 55 Jv Disordered structures amorphous and glassy solids - 75 10 Jm Quantized spin models |
本文献已被 SpringerLink 等数据库收录! |
|