Quantum electronic conductance of a terminal junction

We rigorously treat the quantum mechanical propagation of a two-dimensional electron gas through multiterminal junctions. The elements Rmn,kl of B̈ttiker's global resistance tensor are calculated for ballistic motion. Our results confirm the occurrence of negative resistance observed in recent experiments and predict oscillations of the resistance as a function of ka, where k is the electron Fermi momentum and a is the geometrical dimension of the junction leads.