Abstract
In this talk, we report on a few remarkable transport properties of
lithium-6 atoms through a quantum point contact (QPC) precisely defined
by a set of optical potentials. The versatility of cold-atom techniques
allows us to directly measure heat or spin currents and to tune
interatomic interactions.
In a first experiment
performed with a unitary Fermi gas close to the superfluid transition,
we probe the thermoelectric effects induced by a temperature difference
across the QPC. We show that the system evolves towards a
non-equilibrium steady state, associated with a reduced heat diffusion
and a strong violation of the Wiedemann-Franz law.
In
a second experiment performed with weakly interacting atoms, we locally
lift the spin degeneracy of atoms inside the QPC using an optical
tweezer tuned very close to atomic resonance. We observe quantized,
spin-polarized transport that is robust to dissipation and sensitive to
interaction effects on the scale of the Fermi wavelength. These results
open the way to the quantum simulation of efficient thermoelectric and
spintronic devices with cold atoms.