Physical review. B, Condensed matter
Critical-index calculation from Monte Carlo data with use of finite-size scaling and optimization
Y. Gündüç, Okan Tarhan, R. Sever
Abstract
A method of critical index calculation is proposed. The method is based on matching the temperature values of two different size lattices by finding the optimized solution of the equation t'=${\mathit{b}}_{\mathit{T}}^{\mathit{Y}}$t, where t and t' are the reduced temperatures of the lattices, b is the ratio of lattice sizes, and ${\mathit{Y}}_{\mathit{T}}$ is the thermal critical index. The values of t and t' are obtained from the fourth cumulant of the order parameter, which satisfies the relation ${\mathit{Q}}_{\mathit{r}}$(t,L)=${\mathit{Q}}_{\mathit{r}}$(t'L') around the critical point. By using this method, the critical indices of the two-dimensional Ising model and the (2+1)-dimensional lattice gauge theory are calculated. The advantage of the method is that one can obtain the critical point and the critical indices with high accuracy by performing a relatively small number of Monte Carlo iterations.