Spin Gap in Chains with Hidden Symmetries
Abstract
We investigate the formation of spin gap in one-dimensional models characterized by the groups with hidden dynamical symmetries. A family of two-parametric models of isotropic and anisotropic Spin-Rotator Chains characterized by SU(2)x SU(2) and SO(2)x SO(2)x Z_2 x Z_2 symmetries is introduced to describe the transition from SU(2) to SO(4) antiferromagnetic Heisenberg chain. The excitation spectrum is studied with the use of the Jordan-Wigner transformation generalized for o_4 algebra and by means of bosonization approach. Hidden discrete symmetries associated with invariance under various particle-hole transformations are discussed. We show that the spin gap in SRC Hamiltonians is characterized by the scaling dimension 2/3 in contrast to dimension 1 in conventional Haldane problem.
Keywords
Cite
@article{arxiv.cond-mat/0408016,
title = {Spin Gap in Chains with Hidden Symmetries},
author = {M. N. Kiselev and D. N. Aristov and K. Kikoin},
journal= {arXiv preprint arXiv:cond-mat/0408016},
year = {2009}
}
Comments
4 pages, 2 EPS figures