Abstract
The Landauer transport formulation is generalized to the case of a dynamic scatterer with arbitrary energy levels, weakly coupled to a long ideal noninteracting wire. The two-terminal linear conductance of the device is expressed in terms of the (inelastic) scattering cross-sections of the electrons off the scatterer, using a Fermi-liquid picture for the scattering states of the whole system. Assuming unitarity, i.e. the optical theorem, we obtain the same results from a Kubo linear-response treatment and from a Keldysh technique approach.