arXiv:cond-mat/9907431 · Physical review. B, Condensed matter
Three-magnon contribution to the spin correlation function in integer-spin antiferromagnetic chains
Matthew D. P. Horton, Ian K. Affleck
Abstract
The exact form factor for the O(3) nonlinear $\ensuremath{\sigma}$ model is used to predict the three-magnon contribution to the spin correlation function, $S(q,\ensuremath{\omega}),$ near wave vector $q=\ensuremath{\pi}$ in an integer spin, one-dimensional antiferromagnet. The three-magnon contribution is extremely broad and extremely weak; the integrated intensity is $<2%$ of the single-magnon contribution.