Route to supersolidity for the extended Bose-Hubbard model

Iskin, M.

doi:10.1103/physreva.83.051606

Cited by 77 publications

(114 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the Z 2 symmetry is broken in SS, the selection rule for the matrix elements appearing in eqns (20,21) is the same for (k x , k y ) as that for (k x + π, k y + π), so that the NG mode in Fig.5(b) appears both around (0, 0) and (π, π). It turns out that the intensity of the 4th band in the SS phase rapidly decreases toward the boundary to CO.…”

Section: Spin-spin Correlationmentioning

confidence: 99%

“…In the latter, SS region becomes wider when the nearest-neighbor repulsion V is increased. Moreover, when ZV > U , there is no MI and all insulating phases are CO, while the SS region becomes even wider [21]. These behaviors are contrasted with the present phase diagram for the spin model for ZV > U , where, contrary to a naive expectation, it turns out that SS does not expand, but gives way to "SF" for a fixed V , and that the SS region is completely suppressed by "SF" for large enough V (not shown).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Supersolid states in a spin system: Phase diagram and collective excitations

2013

View full text Add to dashboard Cite

Phases analogous to supersolids can be realized in spin systems. Here we obtain the phase diagram of a frustrated dimer spin-1/2 system on a square lattice and study the collective excitation spectra, focusing on the supersolid state (SS). In the phase diagram on a parameter space of the exchange interaction and magnetic field, we find, on top of the SS phase, a phase that has no counterpart in the Bose Hubbard model and this state becomes dominant at the region where the enhancement of SS occurs in the bose Hubbard model. We then investigate the excitation spectrum and spinspin correlation, which can be detected by neutron scattering experiments. We obtain an analytic expression for the spin wave velocity, which agrees with hydrodynamic relations. The intensity of excitation modes in the spin-spin correlation function is calculated and their change in the supersolid and superfluid states is discussed.PACS numbers: 75.10. Jm, 75.40.Gb, 64.70.Tg, 03.75. Kk INTRODUCTIONSupersolid (SS) state is a phase where both offdiagonal long-range order and diagonal-long range order coexist. After the non-classical rotational inertia experiment in He 4 suggested an SS phase, the SS state attracted considerable interest [1]. However, the interpretation of the result is still controversial [2], and efforts to find SS continue. Lattice systems are other candidates to find SS than He 4 . Cold atoms on optical lattices are one of them. A proposal [3] was made based on the fact that the extended bose Hubbard model with a nearest neighbor interaction shows SS [4,5]. Dipole-dipole interaction is also suggested to help realizing SS [6].Another, entirely different avenue to find SS in lattice systems is to consider quantum magnets. This is because certain spin systems can be effectively regarded as bose systems [7][8][9]. After a theoretical proposal of SS in a dimer spin system [10], spin systems are attracting much attention as a promising candidate to find SS phases [10][11][12][13][14][15]. One example is the spin-1 Heisenberg model with an anisotropy, which is effectively obtained from a spin-1 frustrated dimer model [11]. Another example is the spin-1/2 dimer model with large Ising-like exchange anisotropy [10,12]. The anisotropy can be effectively realized in a lattice with large frustration. Ref. [13] has investigated a frustrated spin-1/2 spin-dimer Heisenberg model with spin-isotropic couplings on square lattice( Fig.1), and shown that the model actually exhibits a SS state. However, the study was concentrated on a specific choice of parameters, while the phase diagram in a wider parameter space has yet to be determined. In addition, experimentally relevant properties of the SS phase have not been fully understood, either.These have motivated us, in the present work, to investigate the phase diagram and dynamical properties of the frustrated spin-1/2 dimer Heisenberg model on square lattice. There, we employ the bond operator method as well as the generalized spin wave theory. In the phase diagram on a parameter space of t...

show abstract

Section: Spin-spin Correlationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Supersolid states in a spin system: Phase diagram and collective excitations

2013

View full text Add to dashboard Cite

show abstract

“…[34] is on supersolid phases for strong nearest-neighbor repulsion. The ground-state phase diagrams show that, as the nearest-neighbor repulsion increases, the supersolid phase expands up to large hopping parameters in the phase diagram.…”

Section: Introductionmentioning

confidence: 99%

Ground-state phase diagram of the two-dimensional extended Bose-Hubbard model

2012

View full text Add to dashboard Cite

We investigate the ground-state phase diagram of the soft-core Bose-Hubbard model with the nearest-neighbor repulsion on a square lattice by using an unbiased quantum Monte Carlo method. In contrast to the previous study [P. Sengupta et. al., Phys. Rev. Lett. 94, 207202 (2005)], we present the ground-state phase diagrams up to large hopping parameters. As a result, in addition to the known supersolid above half-filling, we find supersolid even below and at half-filling for large hopping parameters. Furthermore, for the strong nearest-neighbor repulsion, we show that the supersolid phase occupies a remarkably broad region in the phase diagram

show abstract

“…While the Gutzwiller approach is a simple mean-field approximation, it has been extensively applied to describing various properties of the Bose-Hubbard model, such as quantum phase transitions [49][50][51], collective modes [51][52][53][54], the superfluid critical momentum [54,55], and nonequilibrium dynamics [19,[54][55][56][57][58]. In order to describe collective modes of the system, we separate f i,n (t) into its static part and small fluctuations,…”

Section: B Gutzwiller Mean-field Approximationmentioning

confidence: 99%

Localized Higgs modes of superfluid Bose gases in optical lattices: A Gutzwiller mean-field study

Danshita

Tsuchiya

2017

Phys. Rev. A

View full text Add to dashboard Cite

We study effects of a potential barrier on collective modes of superfluid Bose gases in optical lattices. We assume that the barrier is created by local suppression of the hopping amplitude. When the system is in a close vicinity of the Mott transition at commensurate fillings, where an approximate particle-hole symmetry emerges, there exist bound states of Higgs amplitude mode that are localized around the barrier. By applying the Gutzwiller mean-field approximation to the Bose-Hubbard model, we analyze properties of normal modes of the system with a special focus on the Higgs bound states. We show that when the system becomes away from the Mott transition point, the Higgs bound states turn into quasi-bound states due to inevitable breaking of the particlehole symmetry. We use a stabilization method to compute the resonance energy and line width of the quasi-bound states. We compare the results obtained by the Gutzwiller approach with those by the Ginzburg-Landau theory. We find that the Higgs bound states survive even in a parameter region far from the Mott transition, where the Ginzburg-Landau theory fails.

show abstract

Route to supersolidity for the extended Bose-Hubbard model

Cited by 77 publications

References 28 publications

Supersolid states in a spin system: Phase diagram and collective excitations

Supersolid states in a spin system: Phase diagram and collective excitations

Ground-state phase diagram of the two-dimensional extended Bose-Hubbard model

Localized Higgs modes of superfluid Bose gases in optical lattices: A Gutzwiller mean-field study

Contact Info

Product

Resources

About