Bosonisation, cut-offs and the spin wave velocity for the Heisenberg-Ising chain

Abstract

It is demonstrated that applying bosonisation methods to the Fermi system equivalent to the Heisenberg-Ising spin chain gives a rather accurate prediction of the spin wave velocity over a wide range of values of the coupling constant. This suggests that boson predictions of phase velocities are good for a large class of strongly interacting one-dimensional systems.