Shear viscosity and spectral function of the quark matter
  We discuss the shear viscosity of the quark matter by using the Kubo-Mori formula. It is found that the shear viscosity is expressed in terms of the quark spectral function. If the spectral function is approximated by a modified Bright-Wigner type, the viscosity decreases as the width of the spectral function increases. We also discuss dependence of the shear viscosity on the temperature and the density. 
Masaharu Iwasaki, Hiromasa Ohnishi, and Takahiko Fukutome