Shear viscosity to entropy density ratio of nuclear matter by transport model, D. Fang, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, China − The ratio of shear viscosity to entropy density for an equilibrated nuclear system is investigated at intermediate energy heavy-ion collisions within the framework of the Boltzmann-Uehling-Uhlenbeck model.  After the collision system almost reaching a local equilibration, the temperature, pressure and energy density are obtained from the phase-space information and shear viscosity to entropy density ratio is calculated using the Green-Kubo method.  The results show that shear viscosity to entropy density ratio decreases with incident energy and tends toward a smaller value around 0.5, which is close to the BNL Relativistic Heavy Ion Collider results.