Phase Transition in the $2\mathrmD~\mathrmXY$ Model

We present detailed results for the susceptibility Ï, correlation length ξ, and specific heat cν for the XY model. The best fit to Ï and ξ data is obtained by use of the Kosterlitz-Thouless scaling form with ν=0.500(1), but η shows considerable deviation from ¼ down to T=1.03. The critical temperature is estimated to be Tc=0.898(2). The simulations are done on 642, 1282, 2562, and 5122 lattices with use of an overrelaxed algorithm which decorrelates as Ïâ0.15ξ1.2. Similar reduction in critical slowing down is anticipated for all continuous-spin models.