Direct Observation of a Fractional Charge

TL;DR

This paper reports direct measurements of fractional quasiparticle charge in the Fractional Quantum Hall regime using quantum shot noise, confirming the e/3 charge predicted by Laughlin at a filling factor of 1/3.

Contribution

It provides the first direct experimental observation of fractional charge in the Fractional Quantum Hall effect via shot noise measurements.

Findings

Quasiparticle charge measured as e/3 at filling factor 1/3

Shot noise proportional to quasiparticle charge

Experimental confirmation of Laughlin's prediction

Abstract

We performed measurements of Quantum Shot Noise in order to determine the quasiparticle charge in the Fractional Quantum Hall regime. The noise is generated by a current flow through a partially transmitting Quantum Point Contact in a 2DEG. The noise is directly proportional to the charge of the quasiparticles, thus allowing direct determination of the charge. We measured Quantum Shot Noise at a filling factor of 1/3 and found that the charge is e/3; as predicted by Laughlin.