Tunneling current noise in the fractional quantum Hall effect: when the effective charge is not what it appears to be

TL;DR

This paper investigates how tunneling current noise measurements in the fractional quantum Hall effect can misrepresent the quasiparticles' effective charge, highlighting potential artifacts and genuine dependencies in experimental data.

Contribution

It analyzes two experiments to distinguish between artifacts and real physical effects influencing effective charge measurements.

Findings

One experiment's apparent charge dependence is likely an analysis artifact.

The other experiment's charge dependence appears to be genuine.

Clarifies interpretation of tunneling noise data in fractional quantum Hall systems.

Abstract

Fractional quantum Hall quasiparticles are famous for having fractional electric charge. Recent experiments report that the quasiparticles' effective electric charge determined through tunneling current noise measurements can depend on the system parameters such as temperature or bias voltage. Several works proposed to understand this as a signature for edge theory properties changing with energy scale. I consider two of such experiments and show that in one of them the apparent dependence of the electric charge on a system parameter is likely to be an artefact of experimental data analysis. Conversely, in the second experiment the dependence cannot be explained in such a way.