Quasiparticle tunneling in the lowest Landau level

Tunneling between two close-by edge states is a potentially powerful probe of topological order in the fractional quantum Hall effect. A fit to experimental data is believed to yield the effective charge and the interaction parameter of current-carrying quasiparticles. However, the robustness of this method has yet to be established. Here, the authors consider the well-understood state at $\ensuremath{\nu}=1/3$ and check whether quasiparticle tunneling measures the expected parameters. While a charge of $e/3$ is observed, the interaction parameter is not universal, and the currently available theory cannot describe data obtained for high channel transmission. At $\ensuremath{\nu}=4/3$, the data suggest that only an inner Laughlin edge mode contributes to tunneling.