Acta Physica Sinica
A TRANSVERSE XY MODEL WITH NEXT NEAREST NEIGHBOUR INTERACTIONS
Xu Bo-wei, TANG KUN-FA, 上海交通大学物理系
Abstract
We generalize the transverse XY model to the case with NNN interactions. The Hamiltonian is H=g∑nσn2-∑n ((1+γ)/2σnxσn+1x+(1-γ)/2σnyσn+1y)-λ∑n ((1+β)/2σnxσn+2x+(1-β)/2σnyσn+2y). It is shown that the model with β=0 and γ≠0 isequivalent to the free fermion field in the vicinity of critical point, so that it belongs to the Ising universality class.