arXiv:cond-mat/9803090 · Journal of the Physical Society of Japan
Kosterlitz-Thouless Transition of QuantumXYModel in Two Dimensions
Kenji Harada, Naoki Kawashima
Abstract
The two-dimensional $S=1/2$ XY model is investigated with an extensive quantum Monte Carlo simulation. The helicity modulus is precisely estimated through a continuous-time loop algorithm for systems up to $128 \times 128$ near and below the critical temperature. The critical temperature is estimated as $T_{\rm KT} = 0.3427(2)J$. The obtained estimates for the helicity modulus are well fitted by a scaling form derived from the Kosterlitz renormalization group equation. The validity of the Kosterlitz-Thouless theory for this model is confirmed.