title: Interaction-controlled transport of an ultracold fermi gas.
abstract: We explore the transport properties of an interacting Fermi gas in a three-dimensional optical lattice. The center of mass dynamics of the atoms after a sudden displacement of the trap minimum is monitored for different interaction strengths and lattice fillings. With increasingly strong attractive interactions the weakly damped oscillation, observed for the noninteracting case, turns into a slow relaxational drift. Tuning the interaction strength during the evolution allows us to dynamically control the transport behavior. Strong attraction between the atoms leads to the formation of local pairs with a reduced tunneling rate. The interpretation in terms of pair formation is supported by a measurement of the number of doubly occupied lattice sites. This quantity also allows us to determine the temperature of the noninteracting gas in the lattice to be as low as (27+/-2)% of the Fermi temperature.
authors.affiliation: Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Niels
authors.initials: N
authors.lastname: Strohmaier
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Takasu
authors.forename: Kenneth
authors.initials: K
authors.lastname: Günter
authors.forename: Robert
authors.initials: R
authors.lastname: Jördens
authors.forename: Michael
authors.initials: M
authors.lastname: Köhl
authors.forename: Henning
authors.initials: H
authors.lastname: Moritz
authors.forename: Tilman
authors.initials: T
authors.lastname: Esslinger