title: Dynamical spin structure factor for the anisotropic spin-1/2 Heisenberg chain.
abstract: The longitudinal spin structure factor for the XXZ-chain at small wave vector q is obtained using Bethe ansatz, field theory methods, and the density matrix renormalization group. It consists of a peak with a peculiar, non-Lorentzian shape and a high-frequency tail. We show that the width of the peak is proportional to q2 for finite magnetic field compared to q3 for a zero field. For the tail we derive an analytic formula without any adjustable parameters and demonstrate that the integrability of the model directly affects the line shape.
authors.affiliation: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: R G
authors.initials: RG
authors.lastname: Pereira
authors.forename: J
authors.initials: J
authors.lastname: Sirker
authors.forename: J-S
authors.initials: JS
authors.lastname: Caux
authors.forename: R
authors.initials: R
authors.lastname: Hagemans
authors.forename: J M
authors.initials: JM
authors.lastname: Maillet
authors.forename: S R
authors.initials: SR
authors.lastname: White
authors.forename: I
authors.initials: I
authors.lastname: Affleck