Progress of Theoretical and Experimental Physics
A Machine Learning Study of the 2D Antiferromagnetic Ising Model with Nearest and Next-to-Nearest Interactions on the Triangular Lattice
Shang-Wei Li, Yuan-Heng Tseng, Kai-Wei Huang, Fu-Jiun Jiang
Abstract
Abstract We study the phase transitions of the 2D antiferromagnetic Ising model with nearest $J_1$ and next-to-nearest $J_2$ interactions on the triangular lattice for $J_2/J_1 = 0.1, 0.5$, and 1.0. The method of supervised neural networks (NNs) is employed for the investigation. Although supervised NN is used, no real spin configurations are needed for the training. In addition, two kinds of configurations which have their spins arranged in a staggered pattern are considered as the training set. Remarkably, with this unconventional training strategy, not only are the critical temperatures of the studied $J_2/J_1$ computed accurately by the resulting NN, but also the nature of the investigated phase transitions is determined correctly. Specifically, the phase transitions associated with $J_2/J_1 = 0.1, 0.5$, and 1.0 are first order. These conclusions are consistent with the known results obtained by other methods. Since the training strategy is simple, the NN calculations are highly efficient. It remains to be examined whether the unconventional training approach considered in this study can be used to investigate other models with untypical phase transitions or with nontrivial ground-state configurations.