résumé :

We propose to study a two-species Fermi gas (e.g. 40K-6Li mixture) in which one species is confined in 2D planes or 1D lines and interacts with the other species in the 3D space by a tunable short-range interaction. We show that such a Fermi gas in « mixed dimensions » has rich physics both in few-body and many-body physics.

In few-body physics, the confinement acting only on one species can induce a new type of resonances both in 2-body and 3-body scatterings. In particular, the 3-body resonances are due to the emergence of the Efimov effect that does not exist in the 40K-6Li mixture in a free space.

In many-body physics, the system has a very rich phase diagram in the plane of the effective scattering length and the layer separation. Resulting phases include an interlayer s-wave pairing, an intralayer p-wave pairing, a dimer Bose-Einstein condensation, and a Fermi gas of Efimov-like trimers.

References :

• [1] « Universal Fermi gases in mixed dimensions » Phys. Rev. Lett. 101, 170401 (2008) http://arxiv.org/abs/0806.2668
• [2] « Confinement-induced Efimov resonances in Fermi-Fermi mixtures » Phys. Rev. A 79, 060701(R) (2009) http://arxiv.org/abs/0903.3633
• [3] « Induced p-wave superfluidity in two dimensions » Annals Phys. 324, 897 (2009) http://arxiv.org/abs/0810.1321
• [4] « Phases of a bilayer Fermi gas » http://arxiv.org/abs/0906.4584

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