High Resolution Study of the 2D ANNNI Model Using a Two-replica Cluster Algorithm and Population Annealing (opens in new tab)

The axial next-nearest-neighbor Ising (ANNNI) model in two dimensions is studied using population annealing combined with a two-replica cluster algorithm. We are able to fully resolve the sequence of sharp specific heat peaks that characterize the finite-size incommensurate floating phase. We also show that the two-replica cluster algorithm is much more effective in equilibrating the system than either single-replica cluster methods or the Metro...