  We compute the transport coefficients, namely, the coefficients of shear and
bulk viscosity as well as thermal conductivity for hot and dense quark matter.
The calculations are performed within the Nambu- Jona Lasinio (NJL) model. The
estimation of the transport coefficients is made using a quasiparticle approach
of solving the Boltzmann kinetic equation within the relaxation time
approximation. The transition rates are calculated in a manifestly covariant
manner to estimate the thermal-averaged cross sections for quark-quark and
quark-antiquark scattering. The calculations are performed for finite chemical
potential also. Within the parameters of the model, the ratio of shear
viscosity to entropy density has a minimum at the Mott transition temperature.
At vanishing chemical potential, the ratio of bulk viscosity to entropy
density, on the other hand, decreases with temperature with a sharp decrease
near the critical temperature, and vanishes beyond it. At finite chemical
potential, however, it increases slowly with temperature beyond the Mott
temperature. The coefficient of thermal conductivity also shows a minimum at
the critical temperature.
