Neutral modes edge state dynamics through quantum point contacts

TL;DR

This paper investigates the dynamics of neutral modes in fractional quantum Hall states through a quantum point contact, highlighting the role of neutral modes in tunnelling processes and current fluctuations.

Contribution

It generalizes the effective field theory for edge states to include propagating neutral modes and analyzes the crossover in backscattering current between different quasiparticle tunnelling regimes.

Findings

Neutral modes are essential for explaining the crossover phenomena.

Higher order cumulants reveal the competition between different carrier charges.

The study identifies dominant tunnelling processes in the presence of interactions.

Abstract

Dynamics of neutral modes for fractional quantum Hall states is investigated for a quantum point contact geometry in the weak-backscattering regime. The effective field theory introduced by Fradkin-Lopez for edge states in the Jain sequence is generalized to the case of propagating neutral modes. The dominant tunnelling processes are identified also in the presence of non-universal phenomena induced by interactions. The crossover regime in the backscattering current between tunnelling of single-quasiparticles and of agglomerates of p-quasiparticles is analysed. We demonstrate that higher order cumulants of the backscattering current fluctuations are a unique resource to study quantitatively the competition between different carrier charges. We find that propagating neutral modes are a necessary ingredient in order to explain this crossover phenomena.