Jean-Philippe Brantut, ETH Zurich

Conduction properties of Ultracold Fermions

co-authors: Jakob Meineke, David Stadler, Sebastian Krinner, and Tilman Esslinger

Institute for Quantum Electronics, ETH Zürich

We experimentally study the conduction properties of ultracold fermionic atoms flowing through a quasi two-dimensional channel connecting macroscopic, incoherent reservoirs. An atomic current is induced by creating an imbalance in the particle number of the two reservoirs. Combining the measurement of the current with the high-resolution measurement of the density in the channel, we observe the drop of chemical potential due to the contact resistance which develops at the contacts between the ballistic channel and the reservoirs. Analogous to a field-effect transistor, we use an additional beam to independently tune the atomic density in the channel region and study the current as a function of the chemical potential. For a stronlgy interacting Fermi gas we observe a striking increase of the current which we attribute to the onset of superfluidity. We then investigate the interplay of superfluidity with disorder.