One-dimensional anisotropic Heisenberg model in the transverse magnetic field
Д. В. Дмитриев, V. Ya. Krivnov, А. А. Овчинников +1 more
The one-dimensional spin-1/2 XXZ model in a transverse magnetic field is studied. It is shown that the field induces a gap in the spectrum of the model with the easy-plane anisotropy. Using conformal invariance, the field dependence of the gap is found at small fields. The ground state phase diagram is obtained. It contains four phases with the long-range order of different types and a disordered phase. These phases are separated by critical lines, where the gap and the long-range order vanish. Using scaling estimates, the mean-field approach, and numerical calculations in the vicinity of all critical lines, we find the critical exponents of the gap and the long-range order. It is shown that the transition line between the ordered and disordered phases belongs to the universality class of the transverse Ising model.
arXiv:cond-mat/0204590•Journal of Experimental and Theoretical Physics•Sep 1, 2002•85 citations