Topological effects in short antiferromagnetic Heisenberg chains
Abstract
The manifestations of topological effects in finite antiferromagnetic Heisenberg chains are examined by densitymatrix renormalizationgroup techniques. We find that the difference between integer and halfinteger spin chains shows up in groundstate energy per site when the length of the spin chain is longer than ~ξ, where ξ~exp(πS) is a spinspin correlation length, for spin magnitudes S up to 5/2. For open chains with spin magnitudes S=5/2 to S=5, we verify that end states with fractional spin quantum numbers S' exist and are visible in the structure of the lowenergy excitation spectrum even when the chain length is much smaller than the correlation length ξ. The robustness of end states points to the possibility of the existence of general hidden topological order in quantum spin chains with spin magnitudes S>=1.
 Publication:

Physical Review B
 Pub Date:
 March 2002
 DOI:
 10.1103/PhysRevB.65.104401
 arXiv:
 arXiv:condmat/0006409
 Bibcode:
 2002PhRvB..65j4401L
 Keywords:

 75.10.Jm;
 75.40.Mg;
 Quantized spin models;
 Numerical simulation studies;
 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 4 pages, 6 figures