title: Tracking the effects of interactions on spinons in gapless Heisenberg chains.
abstract: We consider the effects of interactions on spinon excitations in Heisenberg spin-1/2 chains. We compute the exact two-spinon part of the longitudinal structure factor of the infinite chain in zero field for all values of anisotropy in the gapless antiferromagnetic regime, via an exact algebraic approach. Our results allow us to quantitatively describe the behavior of these fundamental excitations throughout the observable continuum, for cases ranging from free to fully coupled chains, thereby explicitly mapping the effects of "turning on the interactions" in a strongly correlated system.
authors.affiliation: Institute for Theoretical Physics, Universiteit van Amsterdam, Science Park 904, Amsterdam, The Netherlands.
authors.forename: Jean-Sébastien
authors.initials: JS
authors.lastname: Caux
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Konno
authors.forename: Mark
authors.initials: M
authors.lastname: Sorrell
authors.forename: Robert
authors.initials: R
authors.lastname: Weston