Transport coefficients for dense hard-disk systems

A study of the transport coefficients of a system of elastic hard disks, based on the use of Helfand-Einstein expressions is reported. The pressure, the viscosity, and the heat conductivity are examined for different density and system-size. While most transport coefficients agree with Enskog theory below the disorder-order transition, a striking power law divergence of the viscosity with density is obtained at this density. The other transport coefficients show a drop in that density regime, relative to the Enskog theoretical prediction. The deviations are related to shear band instabilities and the contept of dilatancy.