Direct Observation of a Fractional Charge

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.