Model of binary opinion dynamics: Coarsening and effect of disorder.

We propose a model of binary opinion in which the opinion of the individuals changes according to the state of their neighboring domains. If the neighboring domains have opposite opinions then the opinion of the domain with the larger size is followed. Starting from a random configuration, the system evolves to a homogeneous state. The dynamical evolution shows a scaling behavior with the persistence exponent theta approximately 0.235 and dynamic exponent z approximately 1.02 + or - 0.02. Introducing disorder through a parameter called rigidity coefficient rho (probability that people are completely rigid and never change their opinion), the transition to a heterogeneous society at rho=0(+) is obtained. Close to rho=0, the equilibrium values of the dynamic variables show power-law scaling behavior with rho. We also discuss the effect of having both quenched and annealed disorder in the system.