Ultra high temperature superfluidity in ultracold atomic Fermi gases with mixed dimensionality.

Achieving a higher superfluid transition $T_c$ has been a goal for the fields of superconductivity and atomic Fermi gases. Here we propose that, by using mixed dimensionality, one may achieve ultra high temperature superfluids in two component atomic Fermi gases, where one component feels a regular three-dimensional (3D) continuum space, while the other is subject to a 1D optic lattice potential. Via tuning the lattice spacing and trap depth, one can effectively raise the Fermi level dramatically upon pairing so that superfluidity may occur at an ultra high temperature (in units of Fermi energy) even beyond the quantum degeneracy regime, well surpassing that in an ordinary 3D Fermi gas and all other known superfluids and superconductors.