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

TL;DR

This study demonstrates the control and observation of superfluid flow in strongly interacting fermions within a quasi-2D channel, revealing the transition to superfluidity by manipulating a gate potential, akin to a field-effect transistor.

Contribution

It introduces a method to control and measure superfluid flow in strongly interacting fermions using a gate potential, providing new insights into superfluidity in atomic gases.

Findings

Observation of superfluid flow onset in strongly interacting fermions.

Control of atomic current via gate potential analogous to electronic transistors.

Comparison showing differences between strongly and weakly interacting Fermi gases.

Abstract

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.