COMPARING CONDUCTANCE QUANTIZATION IN QUANTUM WIRES AND QUANTUM HALL SYSTEMS

We suggest a means to calculate the de conductance of a one-dimensiona l electron system described by the Luttinger model. Our approach is ba sed on the ideas of Landauer and Buttiker on transport in ballistic ch annels and on the methods of current algebra. We analyze in detail the way in which the system can be coupled to external reservoirs. This d etermines-whether the conductance is renormalized or not. We provide a parallel treatment of a quantum wire and a fractional quantum Hall sy stem on a cylinder with two widely separated edges. Although both syst ems are described by the same effective theory, the physical electrons are identified with different types of excitations, and hence the cou pling to external reservoirs is different. As a consequence, the condu ctance in the wire is quantized in integer units of e(2)/h per spin or ientation whereas the Hall conductance allows for fractional quantizat ion.