title: Novel superfluidity in a trapped gas of Fermi atoms with repulsive interaction loaded on an optical lattice.
abstract: We investigate a possibility of superfluidity in a trapped gas of Fermi atoms with a repulsive interaction in the presence of an optical lattice. Applying the exact diagonalization method to a one-dimensional Hubbard model including the trap potential, we find that, when the strength of the repulsive interaction exceeds a critical value, the binding energy of two Fermi atoms becomes negative below the half-filling case, indicating that an attractive interaction effectively works between Fermi atoms. In this case, a "Mott insulating core" appears in the center of the trap, where each site is occupied by one atom. The Cooper-pair correlation strongly develops between atoms in the left- and right-hand sides of this core.
authors.affiliation: CCSE, Japan Atomic Energy Research Institute, 6-9-3 Higashi-Ueno, Taito-ku, Tokyo 110-0015, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Machida
authors.forename: S
authors.initials: S
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Ohashi
authors.forename: H
authors.initials: H
authors.lastname: Matsumoto