Enhanced bulk-edge Coulomb coupling in Fractional Fabry-Perot interferometers

TL;DR

This paper investigates how bulk-edge Coulomb interactions influence fractional quantum Hall interferometers, revealing significant effects even in devices not typically expected to exhibit strong coupling, and reinterpreting recent experimental results at filling factor 5/2.

Contribution

It demonstrates that bulk-edge Coulomb coupling can be substantial in fractional quantum Hall interferometers and provides a new analysis of experimental data considering Majorana states and Coulomb effects.

Findings

Bulk-edge Coulomb effects are significant in certain fractional quantum Hall devices.

Experimental data at ν=5/2 are consistent with Moore-Read topological order.

Coulomb effects may mimic non-abelian braiding signatures in experiments.

Abstract

We study the effects of bulk-edge Coulomb coupling on quantum Hall Fabry-Perot interferometers. We find that these effects can be appreciable in devices which would not usually be associated with strong bulk-edge Coulomb coupling, provided the devices in question exhibit certain fractional plateaus. With this in mind, we analyze recent experiments at $\nu=5/2$ by taking into account a tunnel coupling between localized bulk Majorana states and Majorana edge states. We find that these experimental data are consistent with the widely held view that the $\nu=5/2$ state harbors Moore-Read topological order. However, experiments may have measured Coulomb effects rather than an `even-odd effect' due to non-abelian braiding.