Journal of Physics A Mathematical and General
Conformal invariance and the critical behaviour of a quantum spin Hamiltonian with three-spin coupling
Francisco Castilho Alcaraz, Michael N. Barber
Abstract
A quantum spin model with three-spin coupling is studied by finite-lattice methods. The critical indices nu and alpha are obtained by standard finite-size scaling analysis. Conformal invariance is used to estimate the exponents nu and eta , the central charge or conformal anomaly c and the anomalous dimension of a spin 1/4 parafermion. The authors conclude that the model belongs to the same universality class as the four-state Potts and Baxter-Wu models, although the convergence of the various finite lattice estimators is extremely slow.