Eur. Phys. J. B 39, 335-339 (2004)
https://doi.org/10.1140/epjb/e2004-00198-5

Quantitative expression of the spin gap via bosonization for a dimerized spin-1/2 chain

Laboratoire de Physique Théorique de l'École Normale Supérieure CNRS–UMR8549, 24 rue Lhomond, 75231 Paris Cedex 05, France

Corresponding author: ^a orignac@lpt.ens.fr

Received: 24 February 2004
Published online: 12 July 2004

Abstract

Using results on the mass gap in the sine-Gordon model combined with the exact amplitudes in the bosonized representation of the Heisenberg spin-1/2 chain and one-loop renormalization group, we derive a quantitative expression for the gap in a dimerized spin-1/2 chain. This expression is shown to be in good agreement with recent numerical estimates when a marginally irrelevant perturbation is taken into account.