Metastable superfluidity of repulsive fermionic atoms in optical lattices.
In the fermionic Hubbard model, doubly occupied states have an exponentially large lifetime for strong repulsive interactions U. We show that this property can be used to prepare a metastable s-wave superfluid state for fermionic atoms in optical lattices described by a large-U Hubbard model. When an initial band-insulating state is expanded, the doubly occupied sites Bose condense. A mapping to the ferromagnetic Heisenberg model in an external field allows for a reliable solution of the problem. Nearest-neighbor repulsion and pair hopping are important in stabilizing superfluidity.
Institute of Theoretical Physics, University of Cologne, Zülpicher Strasse 77, 50937 Cologne, Germany.
Achim
A
Rosch
David
D
Rasch
Benedikt
B
Binz
Matthias
M
Vojta