title: Instabilities in binary mixtures of one-dimensional quantum degenerate gases.
abstract: We show that one-dimensional binary mixtures of bosons or of a boson and a spin-polarized fermion are Luttinger liquids with the following instabilities: (i) For different particle densities, strong attraction between the mixture components leads to collapse, while strong repulsion leads to demixing, and (ii) For a low-density mixture of two gases of impenetrable bosons (or a spin-polarized fermion and an impenetrable boson) of equal densities, the system develops a gap and exhibits enhanced pairing fluctuations when there is attraction between the components. In the boson-fermion mixture, the pairing fluctuations occur at finite momentum. Our conclusions apply to mixtures both on the continuum and on optical lattices away from integer or fractional commensurability.
authors: Donostia International Physics Center, Manuel de Lardizabal 4, 20018-Donostia, Spain.
authors: M A
authors: MA
authors: Cazalilla
authors: A F
authors: AF
authors: Ho