Two point-contact interferometer for quantum Hall systems

TL;DR

This paper proposes a two point-contact interferometer for quantum Hall systems to measure fractional charge and statistics of quasiparticles, and analyzes interference effects to distinguish between Fermi-liquid and Luttinger-liquid behaviors.

Contribution

It introduces a novel interferometer device and provides a theoretical framework for measuring fractional charge and statistics in quantum Hall systems.

Findings

Device can measure fractional charge via Aharonov-Bohm period

Interference patterns distinguish Fermi-liquid from Luttinger-liquid behavior

Conductance calculations support experimental realization

Abstract

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.