arXiv:cond-mat/0110095 · Physical review. B, Condensed matter
Connectivity transition in the frustrated S=1 chain revisited
Alexei K. Kolezhuk, U. Schollwöck
Abstract
The phase transition in the antiferromagnetic isotropic Heisenberg $S=1$ chain with frustrating next-nearest-neighbor coupling $\ensuremath{\alpha}$ is reconsidered. We identify the order parameter of the large-\ensuremath{\alpha} phase as describing two intertwined strings, each possessing a usual string order. The transition has a topological nature determined by the change in the string connectivity. Numerical evidence from the density matrix renormalization group results is supported by the effective theory based on soliton states.