title: Anisotropic relaxation dynamics in a dipolar Fermi gas driven out of equilibrium.
abstract: We report on the observation of a large anisotropy in the rethermalization dynamics of an ultracold dipolar Fermi gas driven out of equilibrium. Our system consists of an ultracold sample of strongly magnetic 167Er fermions, spin polarized in the lowest Zeeman sublevel. In this system, elastic collisions arise purely from universal dipolar scattering. Based on cross-dimensional rethermalization experiments, we observe a strong anisotropy of the scattering, which manifests itself in a large angular dependence of the thermal relaxation dynamics. Our result is in good agreement with recent theoretical predictions. Furthermore, we measure the rethermalization rate as a function of temperature for different angles and find that the suppression of collisions by Pauli blocking is not influenced by the dipole orientation.
authors.affiliation: Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
authors.forename: K
authors.initials: K
authors.lastname: Aikawa
authors.affiliation: Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Frisch
authors.affiliation: Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Mark
authors.affiliation: Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Baier
authors.affiliation: Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria and Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Grimm
authors.affiliation: JILA, NIST, and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Bohn
authors.affiliation: JILA, NIST, and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Jin
authors.affiliation: Department of Physics and Astronomy, University of Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark.
authors.forename: G M
authors.initials: GM
authors.lastname: Bruun
authors.affiliation: Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria and Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria.
authors.forename: F
authors.initials: F
authors.lastname: Ferlaino