Kinetics calculation on the shear viscosity in hot QED at finite density
  The shear viscosity of QED plasma at finite temperature and density is calculated by solving Boltzmann equation with variational approach. The result shows the small chemical potential enhances the viscosity in leading-log order by adding a chemical potential quadratic term to the viscosity for the pure temperature environment. 
Hui Liu, Defu Hou and Jiarong Li