Dynamical spin structure factor for the anisotropic spin-1/2 Heisenberg chain.
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.
Pereira
R G
RG
Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1.
Sirker
J
J
Caux
J-S
JS
Hagemans
R
R
Maillet
J M
JM
White
S R
SR
Affleck
I
I