Figure 1

Quantum antidot electrometer. In the experiment, a conductance peak occurs when the occupation of the antidot increments by one particle: an electron on the integer $f=1$ QH plateau, and a Laughlin quasiparticle on the fractional $f=1∕3$ plateau. The measured charge of the particle $q$ is directly proportional to the change in backgate voltage between the conductance peaks. It takes the same gate voltage to attract three $q=e∕3$ quasiparticles as one $q=e$ electron. The $f=1∕3$ conductance data is offset vertically by $0.2e^2∕3h$ for clarity. The dashed vertical lines are guides for the eye.Reuse & Permissions

Figure 2

Aharonov-Bohm periodicity. In the experiment, a conductance peak occurs when an antidot-bound single-particle state crosses the chemical potential. As $B$ is varied, so is the flux $\Phi$ through the antidot area (the area encircled by the tunneling particle). Thus the period $\Delta B$ is a direct measure of the flux period $\Delta \Phi =h∕e$ on both $f=1$ and $f=1∕3$ QH plateaus. Single-valuedness of the wave function requires the Berry’s phase difference between successive states be an integer multiple of $2\pi$. This condition is satisfied by fermionic electrons, but requires a fractional statistical phase contribution by the fractionally-charged Laughlin quasiparticles, as discussed in the text. The dashed vertical lines are guides for the eye.Reuse & Permissions