Polarized superfluidity in the attractive hubbard model with population imbalance.
We study a two-component Fermi system with attractive interactions and different populations of the two species in a cubic lattice. For an intermediate coupling, we find a uniformly polarized superfluid which is stable down to very low temperatures. The momentum distribution of this phase closely resembles that of the Sarma phase, characterized by two Fermi surfaces. This phase is shown to be stabilized by a potential energy gain, as in a BCS superfluid, in contrast with the unpolarized Bose-Einstein condensate which is stabilized by kinetic energy. We present general arguments suggesting that preformed pairs in the unpolarized superfluid favor the stabilization of a polarized superfluid phase.
Dao
Tung-Lam
TL
Centre de Physique Théorique, CNRS, Ecole Polytechnique, F-91128 Palaiseau Cedex, France.
Ferrero
Michel
M
Georges
Antoine
A
Capone
Massimo
M
Parcollet
Olivier
O