COLLECTIVE MODES AND ELECTRONIC SPECTRAL-FUNCTION IN SMOOTH EDGES OF QUANTUM HALL SYSTEMS

We present a microscopic theory of the collective modes of a ''smooth' ' edge of a quantum Hall system, showing under what conditions these m odes can be described as a set of independent bosons. We then calculat e the electronic spectral function in an independent-boson model-a pro cedure that reduces to standard bosonization in the limit of ''sharp'' edge. The I-V tunneling characteristics deduced from this model exhib it, for low voltage, a power-law behavior, with exponents that differ significantly from those of the sharp edge model.