Observing the Drop of Resistance in the Flow of a Superfluid Fermi Gas

In this work, we investigate the conduction properties of strongly interacting fermions flowing through a quasi two-dimensional, multimode channel, which connects two atomic reservoirs. The atomic current in the channel is controlled using a repulsive potential created by an off-resonant laser beam. In analogy with an electronic field-effect transistor, this gate potential controls the chemical potential in the channel while keeping the temperature imposed by the reservoirs unchanged. With the gate potential as a control parameter, we measure the current through the channel over a large dynamic range and determine the density distribution in the channel region. This allows us to observe the onset of superfluid flow of strongly interacting fermions. These measurements are compared to the case of a weakly interacting Fermi gas.