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 investigated by searching for the fastest process of charge relaxation between the edges. The tunneling rate of the fractional charge across a n ­ 1y3 Laughlin state of width Y on the cylinder is found to fit t1y3 ~ expf2aY 2y12l2g, where l is the Landau length, and a . 1.0. This rate is exponentially larger than the electron tunneling rate, and can be interpreted by analogy to the tunneling of a vortex through a superfluid. Fractional charge tunneling dominates current relaxation. It determines the Aharonov-Bohm oscillation period, and the magnitude of quantum shot-noise. [S0031-9007(97)05065-5]