Abstract
We study the spin-gap phase in the one-dimensional - model, assuming that it is caused by the backward scattering process. Based on the renormalization group analysis and symmetry, we can determine the transition point between the Tomonaga-Luttinger liquid and the spin-gap phases, by the level crossing of the singlet and the triplet excitations. In contrast to the previous works, the obtained spin-gap region is unexpectedly large. We also determine that the universality class of the transition belongs to the SU(2) Wess-Zumino-Witten model.
- Received 20 June 1997
DOI:https://doi.org/10.1103/PhysRevLett.79.3214
©1997 American Physical Society