title: Multiparticle composites in density-imbalanced quantum fluids.
abstract: We consider two-component one-dimensional quantum gases with a density imbalance. While generically such fluids are two-component Luttinger liquids, we show that if the ratio of the densities is a rational number, p/q, and mass asymmetry between components is sufficiently strong, one of the two eigenmodes acquires a gap. The gapped phase corresponds to (algebraic) ordering of (p+q)-particle composites. In particular, for attractive mixtures, this implies that the superconducting correlations are destroyed. We illustrate our predictions by numerical simulations of the fermionic Hubbard model with hopping asymmetry.
authors.affiliation: Laboratoire de Physique Théorique et Modèles statistiques, Université Paris-Sud, 91405 Orsay, France.
authors.forename: Evgeni
authors.initials: E
authors.lastname: Burovski
authors.forename: Giuliano
authors.initials: G
authors.lastname: Orso
authors.forename: Thierry
authors.initials: T
authors.lastname: Jolicoeur