Measurement of integer and fractional quantum Hall states in electronic Fabry-Perot interferometers.

Here we present measurements of electronic Fabry-Perot interferometers operating in the quantum Hall regime. Fabry-Perot interferometry can be used to extract the effective charge and statistics of quasiparticles at fractional states. The devices are fabricated on high mobility GaAs/AlGaAs heterostructures and are measured in a dilution refrigerator at T\textasciitilde 10mK. We have measured Coulomb blockade oscillations at numerous integer states as well as at the $\nu =$5/3 fractional quantum Hall state; this allowed us to extract an effect charge e* $=$ e/3 at $\nu $ $=$ 5/3. Efforts are underway to fabricate interferometers which can operate in the pure Aharonov-Bohm regime, where quasiparticle statistics can be probed, and to extend these results to fractional states in the 2nd Landau level.