Homogeneous Atomic Fermi Gases

Abstract

We report on the creation of homogeneous Fermi gases of ultracold atoms in a uniform potential. In the momentum distribution of a spin-polarized gas, we observe the emergence of the Fermi surface and the saturated occupation of one particle per momentum state: the striking consequence of Pauli blocking in momentum space for a degenerate gas. Cooling a spin-balanced Fermi gas at unitarity, we create homogeneous superfluids and observe spatially uniform pair condensates. For thermodynamic measurements, we introduce a hybrid potential that is harmonic in one dimension and uniform in the other two. The spatially resolved compressibility reveals the superfluid transition in a spin-balanced Fermi gas, saturation in a fully polarized Fermi gas, and strong attraction in the polaronic regime of a partially polarized Fermi gas.

Vortex mass in a superfluid

“…A systematic study of the vortex mass could be performed using cold atom gases trapped in bucket potentials by varying the radial position and the core size of the vortex in the superfluid. Uniform trapping geometries suitable for such experiments are already being used by several groups [62][63][64][65]. Controlling the vortex size and position could be achieved by first nucleating several vortices in the system using standard methods and then waiting until only one vortex remains.…”

Mesoscopic quantum superpositions in bimodal Bose-Einstein condensates: Decoherence and strategies to counteract it

“…For simplicity, and taking into account recent experiments on degenerate gases in flat bottom potentials [38,39], we assume in this section that each spin component is trapped in a cubic box of volume V = L 3 with periodic boundary conditions. One can then take advantage of the fact that the Bogoliubov mode functions are plane waves with known amplitudes, which makes explicit calculations straightforward.…”

Local photoemission spectra and effects of spatial inhomogeneity in the BCS-BEC-crossover regime of a trapped ultracold Fermi gas

“…Very recently, for a 6 Li Fermi gas in a cylindrical trap potential (where atoms feel almost uniform potential in the central region), Zwierlein and co-workers have measured the atomic momentum distribution, to observe a clear signature of the Fermi surface formation below the Fermi temperature T F [28].…”