Staggered ground states in an optical lattice

Johnstone, Dean; Westerberg, Niclas; Duncan, Callum W.; Öhberg, Patrik

doi:10.1103/physreva.100.043614

Cited by 14 publications

(17 citation statements)

References 54 publications

(89 reference statements)

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“…It is to be expected that the mean-field phase diagrams would converge between periodic and quasicrystalline lattices with no random onsite disorder as shown in figure 10(a) [88,89]. When random disorder is included, we observe the same features as expected from previous results on disorder in periodic lattices [1].…”

Section: Disordered Vertex Modelsupporting

confidence: 85%

The mean-field Bose glass in quasicrystalline systems

Johnstone

Öhberg

Duncan

2021

J. Phys. A: Math. Theor.

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We confirm the presence of a mean-field Bose glass (BG) in 2D quasicrystalline Bose-Hubbard models. We focus on two models where the aperiodic component is present in different parts of the problem. First, we consider a 2D generalisation of the Aubry-André (AA) model, where the lattice geometry is that of a square with a quasiperiodic onsite potential. Second, we consider the randomly disordered vertex model, which takes aperiodic tilings with non-crystalline rotational symmetries, and forms lattices from the vertices and lengths of the tiles. For the disordered vertex models, the mean-field BG forms across large ranges of the chemical potential, and we observe no significant differences from the case of a square lattice with uniform random disorder. Small variations in the critical points in the presence of random disorder between quasicrystalline and crystalline lattice geometries can be accounted for by the varying coordination number and the different rotational symmetries present. In the 2D AA model, substantial differences are observed from the usual phase diagrams of crystalline disordered systems. We show that weak modulation lines can be predicted from the underlying potential and may stabilise or suppress the mean-field BG in certain regimes. This results in a lobe-like structure for the mean-field BG in the 2D AA model, which is significantly different from the case of random disorder. Together, the two quasicrystalline models studied in this work show that the mean-field BG phase is present, as expected for

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Section: Disordered Vertex Modelsupporting

confidence: 85%

The mean-field Bose glass in quasicrystalline systems

Johnstone

Öhberg

Duncan

2021

J. Phys. A: Math. Theor.

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“…In the rest of this section we discuss the detailed form of Ĥ(1) α and of Ĥ(2) α . The Hamiltonian Ĥ(1) α reads [36,41,44] Ĥ (1) α =V…”

Section: A Extended Bose-hubbard Hamiltonianmentioning

confidence: 99%

“…The SF order parameter has thus a Fourier component at q = π. The alternating sign of the local superfluid parameter leads to the denomination "staggered superfluidity" (SSF) [41]. We now consider the power-law behaviour of the interactions, and thus the coupling to the other neighbours.…”

Section: B Staggered Superfluiditymentioning

confidence: 99%

“…We identify the parameter regime where the interaction-induced hopping terms become of the same order as the kinetic energy and determine the resulting ground state phase diagram. The phase diagram is numerically determined for a canonical ensemble at zero temperature and at density ρ = 2 by means of a DMRG program [39,40], the phases are characterized using the classification discussed in [41]. We find several remarkable properties.…”

Section: Introductionmentioning

confidence: 99%

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Superfluid phases induced by the dipolar interactions

Kraus,

Biedroń,

Zakrzewski

et al. 2020

Preprint

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We determine the quantum ground state of dipolar bosons in a quasi one-dimensional optical lattice and interacting via s-wave scattering. The Hamiltonian is an extended Bose-Hubbard model which includes hopping terms due to the interactions. We identify the parameter regime for which the coefficients of the interaction-induced hopping terms become negative. For these parameters we numerically determine the phase diagram for a canonical ensemble and by means of DMRG. We show that at sufficiently large values of the dipolar strength there is a quantum interference between the tunnelling due to single-particle effects and the one due to the interactions. Because of this phenomenon, incompressible phases appear at relatively large values of the single-particle tunnelling rates. This quantum interference cuts the phase diagram into two different, disconnected superfluid phases. In particular, at vanishing kinetic energy the phase is always superfluid with a staggered superfluid order parameter. These dynamics emerge from quantum interference phenomena between quantum fluctuations and interactions and shed light into their role in determining the thermodynamic properties of quantum matter.

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“…Besides, the Hubbard model with this term has an exact solution in a special point of the parameter space [22][23][24][25]. On the other hand, the extended boson Hubbard model with a density-dependent hopping is an effective Hamiltonian for bosonic molecules, typically polar species [26][27][28], in optical lattices [29][30][31][32][33][34][35][36]. Further, general correlated hop-ping hard-core bosonic Hamiltonians are investigated to understand the physics of frustrated insulating magnetic materials [29][30][31]37].…”

Section: Introductionmentioning

confidence: 99%

The role of density-dependent magnon hopping and magnon-magnon repulsion in ferrimagnetic spin-(1/2, $S$) chains in a magnetic field

da Silva,

Montenegro-Filho

2021

Preprint

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We compare the ground-state features of alternating ferrimagnetic chains (1/2, S) with S = 1, 3/2, 2, 5/2 in a magnetic field and the corresponding Holstein-Primakoff bosonic models up to order s/S, with s = 1/2, considering the fully polarized magnetization as the boson vacuum. The singleparticle Hamiltonian is a Rice-Mele model with uniform hopping and modified boundaries, while the interactions have a correlated (density-dependent) hopping term and magnon-magnon repulsion. The magnon-magnon repulsion increases the many-magnon energy and the density-dependent hopping decreases the kinetic energy. We use density matrix renormalization group calculations to investigate the effects of these two interaction terms in the bosonic model, and display the quantitative agreement between the results from the spin model and the full bosonic approximation. In particular, we verify the good accordance in the behavior of the edge states, associated with the ferrimagnetic plateau, from the spin and from the bosonic models. Furthermore, we show that the boundary magnon density strongly depends on the interactions and particle statistics..

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Staggered ground states in an optical lattice

Cited by 14 publications

References 54 publications

The mean-field Bose glass in quasicrystalline systems

The mean-field Bose glass in quasicrystalline systems

Superfluid phases induced by the dipolar interactions

The role of density-dependent magnon hopping and magnon-magnon repulsion in ferrimagnetic spin-(1/2, $S$) chains in a magnetic field

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