Spinon Attraction in Spin-1/2 Antiferromagnetic Chains

We derive the representation of the two-spinon wavefunction for the Haldane-Shastry model in terms of the spinon coordinates. This result allows us to rigorously analyze spinon interaction and its physical effects. We show that spinons attract one another. The attraction gets stronger as the size of the system is increased and, in the thermodynamic limit, determines the power law with which the susceptibility diverges.