Physical review. B, Condensed matter
Long-ranged interactingS=1 spin chain with the exact valence-bond-solid state
Hiroki Nakano, Minoru Takahashi
Abstract
A one-dimensional S=1 spin system with bilinear and biquadratic interactions between not only nearest-neighbor pairs of spins but also longer-range pairs is studied. We find the necessary and sufficient conditions between the coupling constants of the interactions under which the valence-bond-solid state is an eigenstate of the system. We consider in detail the interactions up to the next-nearest neighbors and report numerical results for the region where the valence-bond-solid state is the ground state. In a special case, some exact excited states are constructed. \textcopyright{} 1996 The American Physical Society.