APS Viewpoint // Fractional Jumps in Quantum Hall Interferometer

The quantum Hall interferometer consists of a two-dimensional material (blue) with a cavity structure (yellow) in its center. When a magnetic field and a voltage are turned on, currents (red lines) flow along the edge of the material. Reflections at the entrances of the cavity lead to interference effects in the measured conductance. For certain field and voltage values, the interference pattern exhibits phase jumps because of the changes in the number of quasiparticles (orange) inside the cavity. Credit: APS/A. Stonebraker