Luttinger liquid of trimers in Fermi gases with unequal masses

Giuliano Orso ¹, Evgeni Burovski ¹, Thierry Jolicoeur ¹

Physical Review Letters, 104 (2010) 065301

We investigate one dimensional attractive Fermi gases in spin-dependent optical lattices. Starting from the asymmetric Hubbard model, we show that three-body bound states – « trimers » – exist as soon as the two tunneling rates are different. We calculate the binding energy and the effective mass of a single trimer. We then show numerically that for finite commensurate densities $n_\uparrow=n_\downarrow/2$ an energy gap appears, implying that the gas is a one-component Luttinger liquid of trimers with suppressed superfluid ordering. The boundaries of this exotic phase are given.

• 1. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),
  CNRS : UMR8626 – Université Paris XI – Paris Sud