THERMALIZATION OF LONGITUDINAL GLUONS

In the usual real-time finite-temperature gauge theory both the physic al and the unphysical degrees of freedom are thermalised. We discuss t he alternative approach where only the physical transverse components of the gauge field have bare thermal propagators, whereas the unphysic al degrees of freedom are not heated. We show how pinch singularities are avoided: sometimes this requires resummation. If only the hard the rmal loop is included in the resummation, the spatially-longitudinal c omponent of the gauge field, which contains an extra collective plasmo n mode, becomes fully thermalised, though the Faddeev-Popov ghost and the remaining unphysical component of the gauge field remain frozen.