The Bethe Ansatz

@article{2007_Hagemans_JPA_40,
  author={R. Hagemans and J.-S. Caux},
  title={Deformed strings in the {H}eisenberg model},
  journal={J. Phys. A: Math. Theor.},
  volume={40},
  number={49},
  pages={14605},
  OPTurl={http://stacks.iop.org/1751-8121/40/i=49/a=001},
  doi={10.1088/1751-8113/40/49/001},
  year={2007},
  abstract={We investigate solutions to the Bethe equations for the isotropic S = 1/2 Heisenberg chain involving complex, string-like rapidity configurations of arbitrary length. Going beyond the traditional string hypothesis of undeformed strings, we describe a general procedure to construct eigenstates including strings with generic deformations, discuss general features of these solutions and provide a number of explicit examples including complete solutions for all wavefunctions of short chains. We finally investigate some singular cases and show from simple symmetry arguments that their contribution to zero-temperature correlation functions vanishes.}
}