title: Spin-imbalanced quasi-two-dimensional Fermi gases.
abstract: We measure the density profiles for a Fermi gas of (6)Li containing N(1) spin-up atoms and N(2) spin-down atoms, confined in a quasi-two-dimensional geometry. The spatial profiles are measured as a function of spin imbalance N(2)/N(1) and interaction strength, which is controlled by means of a collisional (Feshbach) resonance. The measured cloud radii and central densities are in disagreement with mean-field Bardeen-Cooper-Schrieffer theory for a true two-dimensional system. We find that the data for normal-fluid mixtures are reasonably well fit by a simple two-dimensional polaron model of the free energy. Not predicted by the model is a phase transition to a spin-balanced central core, which is observed above a critical value of N(2)/N(1). Our observations provide important benchmarks for predictions of the phase structure of quasi-two-dimensional Fermi gases.
authors.affiliation: Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.|Department of Physics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: W
authors.initials: W
authors.lastname: Ong
authors.affiliation: Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.|Department of Physics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Chingyun
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: I
authors.initials: I
authors.lastname: Arakelyan
authors.affiliation: Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Thomas