Paper detail

Theory of the Fabry-Perot Quantum Hall Interferometer

We analyze interference phenomena in the quantum-Hall analog of the Fabry-Perot interferometer, exploring the roles of the Aharonov-Bohm effect, Coulomb interactions, and fractional statistics on the oscillations of the resistance as one varies the magnetic field B and/or the voltage V_G applied to a side gate. Coulomb interactions couple the interfering edge mode to localized quasiparticle states in the bulk, whose occupation is quantized in integer values. For the integer quantum Hall effect, if the bulk-edge coupling is absent, the resistance exhibits an Aharonov-Bohm (AB) periodicity, where the phase is equal to the number of quanta of magnetic flux enclosed by a specified interferometer area. When bulk-edge coupling is present, the actual area of the interferometer oscillates as function of B and V_G, with a combination of a smooth variation and abrupt jumps due to changes in the number of quasi-particles in the bulk of the interferometer. This modulates the Aharonov-Bohm phase and gives rise to additional periodicities in the resistance. In the limit of strong interactions, the amplitude of the AB oscillations becomes negligible, and one sees only the new "Coulomb-dominated" (CD) periodicity. In the limits where either the AB or the CD periodicities dominate, a color map of resistance will show a series of parallel stripes in the B-V_G plane, but the two cases show different stripe spacings and slopes of opposite signs. At intermediate coupling, one sees a superposition of the two patterns. We discuss the dependence of the interference intensities on parameters including the temperature and the backscattering strengths of the individual constrictions. We also discuss how results are modified in a fractional quantized Hall system, and the extent to which the interferometer may demonstrate the fractional statistics of the quasiparticles.