Transport coefficients in the early universe

We calculate numerically the electrical conductivity sigma, heat conductivity kappa, and shear viscosity eta of the hot plasma present in the early universe for the temperature interval 1 MeV less than or similar to T less than or similar to 80 GeV. We use the Boltzmann collision equation to compute all the scattering matrix elements and regulate them by the thermal masses of the t- and u-channel particles. No leading order approximation is needed because of the numerical integration routines used. [S0556-2821(98)01518-5].