Finite width in out-of-equilibrium propagators and kinetic theory

► Consistent derivation of kinetic equations including finite width effects. ► Analytical non-equilibrium results through resummation of gradients. ► Systematic extension of the gradient expansion beyond the leading order. ► No problems with pinch singularities or secular oscillations within analytical solutions. ► Generalisation of the fluctuation-dissipation-relation to non-equilibrium systems without backreaction.