DYNAMIC STRUCTURE FACTOR IN ONE-DIMENSIONAL HEISENBERG MAGNETS

The authors have evaluated an expression obtained previously for the dynamical spin correlation function of a linear Heisenberg antiferromagnet. The authors discuss the results in relation to both recent neutron scattering experiments and recent computations for finite chains with S=1/ 2. It is concluded that contributions to the dynamical structure factor from many accumulating low-frequency excitations provide the high-frequency strength required from sum rule arguments for small wavevectors.