Two point-contact interferometer for quantum Hall systems

We propose a device, consisting of a Hall bar with two weak barriers, that can be used to study quantum interference effects in a strongly correlated system. We show how the device provides a way of measuring the fractional charge and fractional statistics of quasiparticles in the quantum Hall effect through an anomalous Aharanov-Bohm period. We discuss how this disentangling of the charge and statistics can be accomplished by measurements at fixed filling factor and at fixed density. We also discuss a another type of interference effect that occurs in the nonlinear regime as the source-drain voltage is varied. The period of these oscillations can also be used to measure the fractional charge, and details of the oscillations patterns, in particular the position of the nodes, can be used to distinguish between Fermi-liquid and Luttinger-liquid behavior. We illustrate these ideas by computing the conductance of the device in the framework of edge state theory and use it to estimate parameters for the experimental realization of this device.