COMPARISON OF TUNNELING RATES OF FRACTIONAL CHARGES AND ELECTRONS ACROSS A QUANTUM HALL STRIP

The fundamental mechanism of current dissipation in a Hall strip is in vestigated by searching for the fastest process of charge relaxation b etween the edges. The tunneling rate of the fractional charge across a nu = 1/3 Laughlin state of width Y on the cylinder is found to fit t( 1/3) proportional to exp[-alpha Y-2/12 lambda(2)], where lambda is the Landau length, and alpha similar or equal to 1.0. This rate is expone ntially larger than the electron tunneling rate, and can be interprete d by analogy to the tunneling of a vortex through a superfluid. Fracti onal charge tunneling dominates current relaxation. It determines the Aharonov-Bohm oscillation period, and the magnitude of quantum shot-no ise.