Quarter-filled supersolid and solid phases in the extended Bose–Hubbard model

Ng, Kwai-Kong; Chen, Y C; Tzeng, Yu-Chin

doi:10.1088/0953-8984/22/18/185601

Cited by 12 publications

(20 citation statements)

References 31 publications

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“…8 of Ref. 7. This indicates that the neglected quantum fluctuations in the mean-field calculations destabilize the supersolid phases and reduce the region of the supersolid phases in the ground-state phase diagram.…”

Section: Ground-state Phase Diagrammentioning

confidence: 76%

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Thermal phase transitions of supersolids in the extended Bose-Hubbard model

2010

Phys. Rev. B

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We investigate numerically the finite-temperature phase diagrams of the extended Bose-Hubbard model in a two-dimensional square lattice. In particular, we focus on the melting of supersolid phases of two different crystal orderings, stripe and star orders, arising from the competition of the nearest-and next-nearest -neighbor interactions in the vicinity of quarter filling. The two crystal orders are the result of broken translational symmetry in either one or in both x, and y directions. The broken gauge symmetry of the supersolids are found to be restored via a Kosterlitz-Thouless transition while the broken translational symmetries are restored via a single second-order phase transition, instead of two second-order transitions in the Ising universality class. On the other hand, the phase transitions between the star and stripe orders are first order in nature.

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Section: Ground-state Phase Diagrammentioning

confidence: 76%

“…The ground-state phase diagrams V 1 vs V 2 at quarter filling have been presented before 5,7 . The star supersolid is found to be stable for a wide region of parameters V 1 and V 2 even at commensurate filling n = 1/4.…”

Section: Ground-state Phase Diagrammentioning

confidence: 99%

Thermal phase transitions of supersolids in the extended Bose-Hubbard model

2010

Phys. Rev. B

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“…1b . The supersolid has a non-vanishing superfluid order parameter combined with a density wave representing diagonal order 19 28 29 30 31 32 33 35 36 37 38 39 40 ( Fig. 1g ).…”

Section: Resultsmentioning

confidence: 99%

“…For weak interactions the ground state is a superfluid phase (SF), whereas for strong interactions a localization of the particles is favored forming the Mott insulator phase (MI) 14 15 16 . Theoretically, extended Bose—Hubbard models with off-site interactions 17 have been studied predicting pair superfluid phases 18 19 20 21 22 23 24 25 , charge-density-wave insulators 19 26 27 28 29 30 31 32 33 34 35 36 and supersolid phases 19 28 29 30 31 32 33 35 36 37 38 39 40 . The latter two phases exhibit a density modulation with respect to neighboring lattice sites and break the inversion symmetry of the lattice Hamiltonian spontaneously in the thermodynamic limit 26 27 .…”

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confidence: 99%

Twisted complex superfluids in optical lattices

Jürgensen

Sengstock

Lühmann

2015

Sci Rep

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We show that correlated pair tunneling drives a phase transition to a twisted superfluid with a complex order parameter. This unconventional superfluid phase spontaneously breaks the time-reversal symmetry and is characterized by a twisting of the complex phase angle between adjacent lattice sites. We discuss the entire phase diagram of the extended Bose—Hubbard model for a honeycomb optical lattice showing a multitude of quantum phases including twisted superfluids, pair superfluids, supersolids and twisted supersolids. Furthermore, we show that the nearest-neighbor interactions lead to a spontaneous breaking of the inversion symmetry of the lattice and give rise to dimerized density-wave insulators, where particles are delocalized on dimers. For two components, we find twisted superfluid phases with strong correlations between the species already for surprisingly small pair-tunneling amplitudes. Interestingly, this ground state shows an infinite degeneracy ranging continuously from a supersolid to a twisted superfluid.

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“…Other phases with more complex symmetries, such as three-sublattice and four-sublattice phases, are affected more strongly by the quantum fluctuations, and the locations are shifted towards the region of much smaller values of J/J c than those of the MF theory. 18,57 Thus, we leave them out of the scope of the rest of this paper, treating only a relatively large-J/J c region.…”

Section: B the Cmf Results For The 4 × 4 Clustermentioning

confidence: 99%

Quantum phases of hardcore bosons with long-range interactions on a square lattice

Yamamoto¹,

Masaki²,

Danshita³

2012

Phys. Rev. B

120

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We study the ground-state phase diagrams of hardcore bosons with long-range interactions on a square lattice using the linear spin-wave theory and a cluster mean-field method. Specifically, we consider the two types of long-range interaction: One consists only of the nearest-and nextnearest-neighbor interactions, and the other is the dipole-dipole interaction that decays with the interparticle distance r as ∼ r −3 . It is known from previous analyses by quantum Monte Carlo methods that a checkerboard supersolid (CSS) is absent in the ground-state phase diagram of the former case while it is present in the latter. In the former, we find that quantum fluctuations around mean-field solutions are enhanced by the direct competition between the checkerboard and striped solid orders and that they destabilize the CSS phase. On the other hand, the emergence of the CSS phase in the latter case can be attributed to the absence of such a competition with other solid orders. We also show that the cluster mean-field method allows for the determination of phase boundaries in a precise quantitative manner when scaling with respect to the cluster size is taken into account. It is found that the phase transition between the superfluid and the solid (or CSS) is of the first order in the vicinity of the particle-hole symmetric line.

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Quarter-filled supersolid and solid phases in the extended Bose–Hubbard model

Cited by 12 publications

References 31 publications

Thermal phase transitions of supersolids in the extended Bose-Hubbard model

Thermal phase transitions of supersolids in the extended Bose-Hubbard model

Twisted complex superfluids in optical lattices

Quantum phases of hardcore bosons with long-range interactions on a square lattice

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