  Collective excitations of a hot QCD medium are the main focus of the present
article. The analysis is performed within semi-classical transport theory with
isotropic and anisotropic momentum distribution functions for the gluonic and
quark-antiquark degrees of freedom that constitutes the hot QCD plasma. The
isotropic/equilibrium momentum distributions for gluons and quarks are based on
a recent quasi-particle description of hot QCD equations of state. The
anisotropic distributions are just the extensions of isotropic ones by
stretching or squeezing them in one of the directions. The hot QCD medium
effects in the model adopted here enter through the effective gluon and quark
fugacities along with non-trivial dispersion relations leading to an effective
QCD coupling constant. Interestingly, with these distribution functions the
tensorial structure of the gluon polarization tensor in the medium turned out
to be similar to the one for the non-interacting ultra-relativistic system of
quarks/antiquarks and gluons . The interactions mainly modify the Debye mass
parameter and , in turn, the effective coupling in the medium. These
modifications have been seen to modify the collective modes of the hot QCD
plasma in a significant way.
