Three-body constrained bosons in a double-well optical lattice (original) (raw)
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Quantum phases of constrained dipolar bosons in coupled one-dimensional optical lattices
Physical Review A
We investigate a system of two-and three-body constrained dipolar bosons in a pair of onedimensional optical lattices coupled to each other by the non-local dipole-dipole interactions. Assuming attractive dipole-dipole interactions, we obtain the ground state phase diagram of the system by employing the cluster mean-field theory. The competition between the repulsive on-site and attractive nearest-neighbor interactions between the chains yields three kinds of superfluids; namely the trimer superfluid, pair superfluid and the usual single particle superfluid along with the insulating Mott phase at the commensurate density. Besides, we also realize simultaneous existence of Mott insulator and superfluid phases for the two-and three-body constrained bosons, respectively. We also analyze the stability of these quantum phases in the presence of a harmonic trap potential.
Phase diagram of two-component bosons on an optical lattice
New Journal of Physics, 2003
We present a theoretical analysis of the phase diagram of two-component bosons on an optical lattice. A new formalism is developed which treats the effective spin interactions in the Mott and superfluid phases on the same footing. Using the new approach we chart the phase boundaries of the broken spin symmetry states up to the Mott to superfluid transition and beyond. Near the transition point, the magnitude of spin exchange can be very large, which facilitates the experimental realization of spin-ordered states. We find that spin and quantum fluctuations have a dramatic effect on the transition making it first order in extended regions of the phase diagram. For Mott states with even occupation we find that the competition between effective Heisenberg exchange and spindependent on-site interaction leads to an additional phase transition from a Mott insulator with no broken symmetries into a spin-ordered insulator.
Commensurate Two-Component Bosons in an Optical Lattice: Ground State Phase Diagram
Physical Review Letters, 2004
Two sorts of bosons in an optical lattice at commensurate filling factors can form five stable superfluid and insulating groundstates with rich and non-trivial phase diagram. The structure of the groundstate diagram is established by mapping d-dimensional quantum system onto a (d + 1)dimensional classical loop-current model and Monte Carlo (MC) simulations of the latter. Surprisingly, the quantum phase diagram features, besides second-order lines, first-order transitions and two multi-critical points. We explain why first-order transitions are generic for models with pairing interactions using microscopic and mean-field (MF) arguments. In some cases, the MC results strongly deviate from the MF predictions.
2018
We analyse the ground-state properties of three-body constrained bosons in a one dimensional optical lattice with staggered hopping analogous to the well known Su-Schrieffer-Heeger(SSH) model. By considering attractive and repulsive on-site interactions between the bosons, we obtain the phase diagram which exhibits various quantum phases. Due to the double-well geometry and three-body constraint several gapped phases such as the Mott insulators and dimer/bond-order phases emerge at commensurate densities in the repulsive interaction regime. Attractive interaction leads to the pair formation which leads to the pair bond order phase at unit filling which resembles the valence-bond solid phase of composite bosonic pairs. The pair bond order phase at unit-filling is found to exhibit effective topological properties due to the lattice structure, such as the presence of polarized paired edge states. Finally we study the emergence and breakdown of Thouless charge pumping of bosonic pairs i...
Quantum Phases of Dipolar Bosons in Optical Lattices
Physical Review Letters, 2002
The ground state of dipolar bosons placed in an optical lattice is analyzed. We show that the modification of experimentally accessible parameters can lead to the realization and control of different quantum phases, including superfluid, supersolid, Mott insulator, checkerboard, and collapse phases.
Physical Review A, 2005
We investigate the superfluid-Mott-insulator quantum phase transition of spin-1 bosons in an optical lattice created by pairs of counterpropagating linearly polarized laser beams, driving an Fg = 1 to Fe = 1 internal atomic transition. The whole parameter space of the resulting two-component Bose-Hubbard model is studied. We find that the phase transition is not always second order as in the case of spinless bosons, but can be first order in certain regions of the parameter space. The calculations are done in the mean-field approximation by means of exact numerical diagonalization as well as within the framework of perturbaton theory. PACS numbers: 03.75.Lm,03.75.Mn,71.35.Lk The superfluid-Mott-insulator quantum phase transition (SMQPT) of spinless bosons in periodic lattices is a secondorder transion, which is characterized by a continuous variation of the order parameter ψ from ψ = 0 (superfluid phase) to ψ = 0 (Mott-insulator phase) if the amplitude of the lattice potential increases [1, 2]. In our recent paper [3], we have shown that the SMQPT in a system of spin-1 bosons can be first order as well . By means of numerical calculations within the framework of the mean-field theory, it was found that in the case of 23 Na the SMQPT is second order if the number of atoms per lattice site n = 1, 3, and it is first order for n = 2. In the case of 87 Rb, the SMQPT was found to be second order for n = 1, 2, 3. In the present work, we continue the study of Ref. . The main purpose is to investigate the whole parameter space of spin-1 bosons and to find the regions where the SMQPT is first and second order for arbitrary n.
Ultracold bosons with 3-body attractive interactions in an optical lattice
The European Physical Journal B, 2009
We study the effect of an optical lattice (OL) on the ground-state properties of one-dimensional ultracold bosons with three-body attraction and two-body repulsion, which are described by a cubicquintic Gross-Pitaevskii equation with a periodic potential. Without the OL and with a vanishing two-body interaction term, soliton solutions of the Townes type are possible only at a critical value of the three-body interaction strength, at which an infinite degeneracy of the ground-state occurs; a repulsive two-body interaction makes such localized solutions unstable. We show that the OL opens a stability window around the critical point when the strength of the periodic potential is above a critical threshold. We also consider the effect of an external parabolic trap, studying how the stability of the solitons depends on matching between minima of the periodic potential and the minimum of the parabolic trap.
Quantum phases of hard-core dipolar bosons in coupled one-dimensional optical lattices
Physical Review A, 2014
Hard-core dipolar bosons trapped in a parallel stack of N ≥ 2 1D optical lattices (tubes) can develop several phases made of composites of particles from different tubes: superfluids, supercounterfluids and insulators as well as mixtures of those. Bosonization analysis shows that these phases are threshold-less with respect to the dipolar interaction, with the key "control knob" being filling factors in each tube, provided the inter-tube tunneling is suppressed. The effective ab-initio quantum Monte Carlo algorithm capturing these phases is introduced and some results are presented. arXiv:1405.4328v1 [cond-mat.other]
Spin-1 bosons with coupled ground states in optical lattices
Physical Review A, 2004
The superfluid-Mott-insulator phase transition of ultracold spin-1 bosons with ferromagnetic and antiferromagnetic interactions in an optical lattice is theoretically investigated. Two counterpropagating linearly polarized laser beams with the angle θ between the polarization vectors (lin-θ-lin configuration), driving an Fg = 1 to Fe = 1 internal atomic transition, create the optical lattice and at the same time couple atomic ground states with magnetic quantum numbers m = ±1. Due to the coupling the system can be described as a two-component one. At θ = 0 the system has a continuous isospin symmetry, which can be spontaneously broken, thereby fixing the number of particles in the atomic components. The phase diagram of the system and the spectrum of collective excitations, which are density waves and isospin waves, are worked out. In the case of ferromagnetic interactions, the superfluid-Mott-insulator phase transition is always second order, but in the case of antiferromagnetic interactions for some values of system parameters it is first order and the superfluid and Mott phases can coexist. Varying the angle θ one can control the populations of atomic components and continuously turn on and tune their asymmetry.
Phase diagram of spin-(1/2) bosons in a one-dimensional optical lattice
Physical Review A, 2010
Systems of two coupled bosonic species are studied using Mean Field Theory and Quantum Monte Carlo. The phase diagram is characterized both based on the mobility of the particles (Mott insulating or superfluid) and whether or not the system is magnetic (different populations for the two species). The phase diagram is shown to be population balanced for negative spin-dependent interactions, regardless of whether it is insulating or superfluid. For positive spin-dependent interactions, the superfluid phase is always polarized, the two populations are imbalanced. On the other hand, the Mott insulating phase with even commensurate filling has balanced populations while the odd commensurate filling Mott phase has balanced populations at very strong interaction and polarizes as the interaction gets weaker while still in the Mott phase.