Spontaneous Symmetry Breaking in a One Dimensional Driven Diffusive System

Abstract
A simple model of a driven diffusive system which exhibits spontaneous symmetry breaking in one dimension is introduced. The model has short range interactions and unbounded noise. It is characterized by an asymmetric exclusion process of two types of charges moving in opposite directions on an open chain. The model is studied by mean field and Monte Carlo methods. Exact solutions can be found in a restricted region of its parameter space. A simple physical picture for the symmetry breaking mechanism is presented.