Stability of the superfluid state in a disordered one-dimensional ultracold fermionic gas

Abstract

We study a one-dimensional Fermi gas with attractive short range-interactions in a disordered potential by the density matrix renormalization group (DMRG) technique. Our results can be tested experimentally by using cold atom techniques. We identify a region of parameters for which disorder enhances the superfluid state. As disorder is further increased, global superfluidity eventually breaks down. However this transition seems to occur before the transition to the insulator state takes place. This suggests the existence of an intermediate metallic “pseudogap” phase characterized by strong pairing but no quasi-long-range order.