Multimer formation in 1D two-component gases and trimer phase in the asymmetric attractive Hubbard model

Abstract

We consider two-component one-dimensional quantum gases at special imbalanced commensurabilities which lead to the formation of multimer (multi-particle bound-states) as the dominant order parameter. Luttinger liquid theory supports a mode-locking mechanism in which mass (or velocity) asymmetry is identified as the key ingredient to stabilize such states. While the scenario is valid both in the continuum and on a lattice, the effects of umklapp terms relevant for densities commensurate with the lattice spacing are also mentioned. These ideas are illustrated and confronted with the physics of the asymmetric (mass-imbalanced) fermionic Hubbard model with attractive interactions and densities such that a trimer phase can be stabilized. Phase diagrams are computed using density-matrix renormalization group techniques, showing the important role of the total density in achieving the novel phase. The effective physics of the trimer gas is as well studied. Lastly, the effect of a parabolic confinement and the emergence of a crystal phase of trimers are briefly addressed. This model has connections with the physics of imbalanced two-component fermionic gases and Bose-Fermi mixtures as the latter gives a good phenomenological description of the numerics in the strong-coupling regime.

17 pages, 15 figures

References in corpus (28)

• Theory of ultracold Fermi gases
• Topological confinement in bilayer graphene
• Exploring an ultracold Fermi-Fermi mixture: Interspecies Feshbach resonances and scattering properties of 6Li and 40K
• Deformation of a Trapped Fermi Gas with Unequal Spin Populations
• Quantum degenerate two-species Fermi-Fermi mixture coexisting with a Bose-Einstein condensate
• Phase diagram of a strongly interacting polarized Fermi gas in one dimension
• Color Superfluidity and "Baryon" Formation in Ultracold Fermions
• Instabilities in binary mixtures of one-dimensional quantum degenerate gases
• Competing orders in one dimensional spin 3/2 fermionic systems
• Pairing states of a polarized Fermi gas trapped in a one-dimensional optical lattice
• Efimov Physics in Cold Atoms
• Density-Matrix Renormalization Group Study of Trapped Imbalanced Fermi Condensates
• Exact Numerical Study of Pair Formation with Imbalanced Fermion Populations
• The FFLO state in the one-dimensional attractive Hubbard model and its fingerprint in the spatial noise correlations
• Spin-1/2 fermions on spin-dependent optical lattices
• Spin 3/2 fermions with attractive interactions in a one-dimensional optical lattice: phase diagrams, entanglement entropy, and the effect of the trap
• Confinement vs Deconfinement of Cooper Pairs in One-Dimensional Spin-3/2 Fermionic Cold Atoms
• The one-dimensional Bose-Fermi-Hubbard model in the heavy-fermion limit
• Three-Component Fermi Gas in a one-dimensional Optical Lattice
• Quantum phase diagram of fermion mixtures with population imbalance in one-dimensional optical lattices
• Pairing of 1D Bose-Fermi mixtures with unequal masses
• Fermi-Fermi Mixtures in the Strong Attraction Limit
• Dynamical creation of a supersolid in asymmetric mixtures of bosons
• Pair formation and collapse in imbalanced Fermion populations with unequal masses
• Boson-Fermion pairing in Bose-Fermi mixtures on 1D optical lattices
• Supersolids in one dimensional Bose Fermi mixtures
• Preemptive vortex-loop proliferation in multicomponent interacting Bose--Einstein condensates
• Stability and pairing in quasi-one-dimensional Bose-Fermi mixtures