Charge tunneling in fractional edge channels

TL;DR

This paper models charge tunneling in fractional quantum Hall edge states, explaining experimental data on effective charge and noise, and proposes higher-order cumulant measurements to validate the quasiparticle bunching scenario.

Contribution

It introduces a hierarchical model for fractional edge states that accounts for non-universal interactions and explains experimental observations of tunneling charges.

Findings

Agreement with experiments at =2/3 and =2/5

Identification of conditions for measuring fundamental quasiparticle charge

Proposal of high-order cumulant measurements for validation

Abstract

We explain recent experimental observations on effective charge of edge states tunneling through a quantum point contact in the weak backscattering regime. We focus on the behavior of the excess noise and on the effective tunneling charge as a function of temperature and voltage. By introducing a minimal hierarchical model different filling factors, \nu=p/(2p+1), in the Jain sequence are treated on equal footing, in presence also of non-universal interactions. The agreement found with the experiments for \nu=2/3 and \nu=2/5 reinforces the description of tunneling of bunching of quasiparticles at low energies and quantitatively defines the condition under which one expects to measure the fundamental quasiparticle charge. We propose high-order current cumulant measurement to cross-check the validity of the above scenario and to better clarify the peculiar temperature behavior of the effective charges measured in the experiments.