On the Two-Magnon Bound States for the Quantum Heisenberg Chain with Variable Range Exchange
J. Dittrich, V. I. Inozemtsev
The spectrum of finite-difference two-magnon operator is investigated for quantum S=1/2 chain with variable range exchange of the form h(j-k)∝ sinh -2a(j-k). It is found that usual bound state appears for some values of the total pseudomomentum of two magnons as for the Heisenberg chain with nearest-neighbor spin interaction. Besides this state, a new type of bound state with oscillating wave function appears at larger values of the total pseudomomentum.
arXiv:solv-int/9612008•Modern Physics Letters B•May 10, 1997•2 citations