# Why a noninteracting model works for shot noise in fractional charge experiments

## TL;DR

This paper explains why a noninteracting model accurately describes shot noise in fractional quantum Hall experiments, despite the strong interactions involved, by proving its validity in certain limits and providing an approximate formula for intermediate regimes.

## Contribution

The authors demonstrate that a noninteracting shot noise formula applies in strong and weak backscattering limits for fractional quantum Hall systems, regardless of microscopic details, and derive an approximate model for intermediate regimes.

## Key findings

- Noninteracting formula holds in strong and weak backscattering limits.
- Derived an approximate, model-independent formula for intermediate backscattering.
- Experimental verification at filling factor 3/5 supports theoretical predictions.

## Abstract

A fractional quasiparticle charge is a manifestation of strong interactions in the fractional quantum Hall effect. Nevertheless, shot noise of quasiparticles is well described by a formula, derived for noninteracting charges. We explain the success of that formula by proving that in the limits of strong and weak backscattering it holds irrespectively of microscopic details in weakly and strongly interacting systems alike. The derivation relies only on principles of statistical mechanics. We also derive an approximate model-independent formula for shot noise in the regime of intermediate backscattering. The equation is numerically close to the standard `noninteracting' fitting formula but suggests a different physical interpretation of the experimental results. We verify our theoretical predictions with a shot noise experiment at the filling factor $3/5$.