Universality of the Ising and the S=1 model on Archimedean lattices: A Monte Carlo determination

TL;DR

This study uses advanced Monte Carlo methods to demonstrate that both the S=1/2 and S=1 Ising models on specific Archimedean lattices share the same critical exponents as the 2D Ising model, confirming universality.

Contribution

The paper provides high-precision Monte Carlo analysis showing the universality of critical exponents for S=1/2 and S=1 Ising models on Archimedean lattices, clarifying previous misconceptions.

Findings

Critical exponents match 2D Ising model values

Finite-size scaling confirms universality

Accurate critical amplitude estimates obtained

Abstract

The Ising model S=1/2 and the S=1 model are studied by efficient Monte Carlo schemes on the (3,4,6,4) and the (3,3,3,3,6) Archimedean lattices. The algorithms used, a hybrid Metropolis-Wolff algorithm and a parallel tempering protocol, are briefly described and compared with the simple Metropolis algorithm. Accurate Monte Carlo data are produced at the exact critical temperatures of the Ising model for these lattices. Their finite-size analysis provide, with high accuracy, all critical exponents which, as expected, are the same with the well known 2d Ising model exact values. A detailed finite-size scaling analysis of our Monte Carlo data for the S=1 model on the same lattices provides very clear evidence that this model obeys, also very well, the 2d Ising model critical exponents. As a result, we find that recent Monte Carlo simulations and attempts to define effective dimensionality for the S=1 model on these lattices are misleading. Accurate estimates are obtained for the critical amplitudes of the logarithmic expansions of the specific heat for both models on the two Archimedean lattices.