Parity-breaking Ising-like model with Spin-Exchange dynamics

We investigate a parity-breaking Ising-like model with Spin-Exchange dynamics using Wang–Landau algorithm. The computed density of states permits the analysis of thermodynamic observables in equilibrium and transport behavior analogous to symmetric simple exclusion process. We observed a density dependent phase transition, where the transition temperature having a minimum at a critical density ρc≈0.4. Below ρc the system shows a diffusive and weakly localized behavior, while above ρc strongly localized behavior due to the particle mobility. The parity breaking term increases the fluctuations in particle current at ρc, which suggests competing transport mechanisms. The spin exchange dynamics alone can induce a non zero particle current even in equilibrium. As temperature increases, the particle current behavior transits from an oscillatory regime to a steady state where transport is stabilized. Furthermore, the increase of the parity breaking interaction parameter raises the transition temperature (TC), which supports the role of interaction driven effects. The specific heat capacity for different number of particles diverges near TC. The canonical energy distribution shows single-peaked distribution, combined with this continuous energy change and entropy change, and divergence near TC in specific heat confirms a second order phase transition.