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

Ohgoe, Takahiro; Suzuki, Takafumi; Kawashima, Naoki

doi:10.1103/physrevb.86.054520

Cited by 65 publications

(70 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The critical exponents of this second-order transition are essentially independent of the polarization angle and are compatible with the 3D Ising universality class within the statistical uncertainty of our simulations. Remarkably, our results show that for large polarization angles the stripe phase can be observed experimentally at densities significantly lower than those required to reach the solid phase and without any optical lattice [23]. Finally, at high densities and large tilting angles the system undergoes a first-order phase transition from the crystal to the stripe phase.…”

mentioning

confidence: 54%

Phase diagram of dipolar bosons in two dimensions with tilted polarization

2014

View full text Add to dashboard Cite

We analyze the ground state of a system of dipolar bosons moving in the XY plane and such that their dipolar moments are all aligned in a fixed direction in space. We focus on the general case where the polarization field forms a generic angle α with respect to the Z axis. We use the path-integral ground-state method to analyze the static properties of the system as both α and the density n vary over a wide range where the system is stable. We use the maximum of the static structure function as an order parameter to characterize the different phases and the transition lines among them. We find that, in addition to a superfluid gas and a solid phase, the system reaches a stripe phase at large tilting angles that is entirely induced by the anisotropic character of the interaction. We also show that the quantum phase transition from the gas to the stripe phase is of second order and report approximate values for the critical exponents. In recent years, dipolar Bose gases have received much attention. The study of quantum degenerate gases of dipolar species has become one of the most active areas of experimental and theoretical research in the field of ultracold atoms [1][2][3]. From the theoretical point of view, the anisotropic and long-range character of the interaction makes dipolar systems unique, exhibiting features such as p-wave superfluidity in two-dimensional (2D) Fermi gases [4] or roton instability [5][6][7][8].Up to now, little attention has been paid to the 2D case where dipoles are polarized along an arbitrary direction, including the analysis of scattering properties [9] or the superfluid and collapse instabilities of a quasi-two-dimensional gas of dipolar fermions aligned by an external field [4]. Experiments such as those reported in Ref. [10] have also investigated the effect of (quasi-)2D confinement of a cloud of dipolar particles. One remarkable feature induced by the anisotropy of the interaction is the emergence of a stripe phase, which has been predicted to appear in both Bose [7] and Fermi [11][12][13] systems. Some calculations, in the mean-field approximation, predict the appearance of stripes even in the isotropic case where all dipoles are polarized perpendicular to the plane of movement, although recent Monte Carlo calculations for dipolar fermions arrived at a different conclusion [14]. In Ref.[7] we used path-integral ground-state (PIGS) calculations to reveal the existence of a stripe phase at large densities and polarization angles in 2D dipolar bosonic systems. In this work we extend the previous analysis and discuss the complete phase diagram at zero temperature, characterizing the stripe phase as a function of the density and polarization angle and determining the corresponding solid and stripe transition lines together with the critical exponents.In previous works we discussed the low-density properties [15] and elementary excitation spectrum [7] of the fully anisotropic 2D dipolar interaction. In this work we extend the analysis and investigate the phase diagram of a 2D system...

show abstract

mentioning

confidence: 54%

Phase diagram of dipolar bosons in two dimensions with tilted polarization

2014

View full text Add to dashboard Cite

show abstract

“…The SS phase, which not only appears along with the DW(21) and DW (32) phases, but also exists along with the DW(10) phase forρ < 1/2, as was predicted earlier through quantum Monte Carlo (QMC) studies in ref. [48]. The MI(1) and MI(2) are the Mott insulating phases with occupation densities ρ A = ρ B = 1 and ρ A = ρ B = 2 respectively.…”

Section: Resultsmentioning

confidence: 99%

Spin‐1 Bose Hubbard Model with Nearest Neighbour Extended Interaction

Nabi

Basu

2017

Annalen der Physik

View full text Add to dashboard Cite

A spinor (F = 1) Bose gas is studied in presence of a density-density interaction through a mean field approach and a perturbation theory for either sign of the spin dependent interaction, namely the antiferromagnetic (AF) and the ferromagnetic cases. In the AF case, the charge density wave (CDW) phase appears to be sandwiched between the Mott insulating (MI) and the supersolid phases for small values of the extended interaction strength. But the CDW phase completely occupies the MI lobe when the extended interaction strength is larger than a certain critical value related to the width of the MI lobes and hence opens up the possibilities of spin singlet and nematic CDW insulating phases. In the ferromagnetic case, the phase diagram shows similar features as that of the AF case and are in complete agreement with a spin-0 Bose gas. The perturbation expansion calculations nicely corroborate the mean field phase results in both these cases. Further, we extend our calculations in presence of a harmonic confinement and obtained the momentum distribution profile that is related to the absorption spectra in order to distinguish between different phases.

show abstract

“…This is the topic of the present paper. Stable supersolid phases have already been found for soft-core bosons in one, two and three dimensions 22,23,36,37,41 . When the contact repulsion, U , is large compared to the near neighbor interaction, V 1 , (the mean field value is U > 4V 1 in two dimensions), the system behaves as in the hard core case and phase separates when doped away from half filling.…”

mentioning

confidence: 98%

“…Rather, there is a thermodynamic instability to phase separation in which different spatial regions are superfluid and charge ordered. Despite the absence of simultaneous diagonal and off-diagonal long range order in this most simple scenario, other lattice geometries have been shown to exhibit supersolid phases, and, indeed, by now there is a considerable numerical literature as a function of lattice geometry, dimensionality, filling and interaction [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] . More exotic processes within the Hamiltonian, such as ring exchange, are also known to play a potential role in supersolidity 38,39 .…”

mentioning

confidence: 99%

Phase stability in the two-dimensional anisotropic boson Hubbard Hamiltonian

et al. 2013

View full text Add to dashboard Cite

The two dimensional square lattice hard-core boson Hubbard model with near neighbor interactions has a 'checkerboard' charge density wave insulating phase at half-filling and sufficiently large intersite repulsion. When doped, rather than forming a supersolid phase in which long range charge density wave correlations coexist with a condensation of superfluid defects, the system instead phase separates. However, it is known that there are other lattice geometries and interaction patterns for which such coexistence takes place. In this paper we explore the possibility that anisotropic hopping or anisotropic near neighbor repulsion might similarly stabilize the square lattice supersolid. By considering the charge density wave structure factor and superfluid density for different ratios of interaction strength and hybridization in thex andŷ directions, we conclude that phase separation still occurs.

show abstract

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

Cited by 65 publications

References 53 publications

Phase diagram of dipolar bosons in two dimensions with tilted polarization

Phase diagram of dipolar bosons in two dimensions with tilted polarization

Spin‐1 Bose Hubbard Model with Nearest Neighbour Extended Interaction

Phase stability in the two-dimensional anisotropic boson Hubbard Hamiltonian

Contact Info

Product

Resources

About