title: Superfluid-insulator transitions of the fermi gas with near-unitary interactions in a periodic potential.
abstract: We consider spin-1/2 fermions of mass m with interactions near the unitary limit. In an applied periodic potential of amplitude V and period a_{L}, and with a density of an even integer number of fermions per unit cell, there is a second-order quantum phase transition between superfluid and insulating ground states at a critical V=V_{c}. We compute the universal ratio V_{c}ma_{L};{2}/variant Planck's over 2pi;{2} at N=infinity in a model with Sp(2N) spin symmetry. The insulator interpolates between a band insulator of fermions and a Mott insulator of fermion pairs. We discuss implications for recent experiments.
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Eun Gook
authors.initials: EG
authors.lastname: Moon
authors.forename: Predrag
authors.initials: P
authors.lastname: Nikolić
authors.forename: Subir
authors.initials: S
authors.lastname: Sachdev