We have calculated the probability distribution for the staggered magnetization at T=0 for the 2D antiferromagnetic quantum XY model on finite lattices. For the ground state, the distribution shows evidence of isotropic magnetization ordering on the xy-plane. Based on data on seven lattices up to 26 sites, the extrapolated value of the staggered magnetization is 0.448±0.003 in the thermodynamic limit. © 1988.
Tang, S. (1988). Zero-temperature ordering in the two-dimensional quantum XY model. Physics Letters A, 129(2), 83–87. https://doi.org/10.1016/0375-9601(88)90074-6