Hard Loop Approach to Anisotropic Systems
  Anisotropic systems of quarks and gluons, which at least for sufficiently short space-time intervals can be treated as homogeneous and static, are considered. The gluon polarization tensor of such a system is explicitly computed within the semiclassical kinetic and Hard Loop diagrammatic theories. The equivalence of the two approaches is demonstrated. The quark self energy is computed as well, and finally, the dispersion relations of quarks and gluons in the anisotropic medium are discussed. 
Stanislaw Mrowczynski and Markus H. Thoma