Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Communications in Theoretical Physics

Finite-momentum superfluid and supersolid phases in a spin-orbit-coupled spin-1 Bose-Hubbard model with nearest-neighbor interaction

Ji-Guo Wang, Fang-Ru Jin

Published Sep 30, 2026• 0 citations
Publisher

Abstract

Abstract The interplay between spin-orbit coupling (SOC) and nearest-neighbor (NN) repulsion in optical lattices provides a fertile ground for realizing exotic quantum phases that simultaneously host finite-momentum condensation and spontaneous density modulation. We address this interplay for spin-1 bosons in a two-dimensional square lattice with Rashba SOC and NN interactions, employing the single-site Gutzwiller mean-field (SGMF) method as our primary tool and the $2\times2$ cluster Gutzwiller mean-field (CGMF) approach as a systematic check of short-range correlation effects. Our central finding is that SOC fundamentally reconstructs the single-particle band structure, shifting the lowest-band minimum from zero to finite momenta with increasing SOC strength. This reconstruction underpins a cascade of modulated superfluid (SF) phases-stripe, square, twist, and checkerboard-whose condensate textures are dictated predominantly by SOC. The addition of NN repulsion naturally favors real-space density ordering; the competition and cooperation between this density order and SOC-generated phase textures then stabilize a family of supersolid (SS) phases that mirror the same four modulated patterns, in which finite-momentum condensate and density-wave orders coexist. To complement the numerical phase diagrams, we derive semi-analytical phase boundaries for both the Mott-insulator (MI)-SF and density-wave (DW)-SS transitions using second-order perturbation theory. These expressions not only reproduce the overall trends of the SGMF results but also provide a transparent physical picture of the underlying instability mechanisms. Importantly, the representative CGMF calculations retain the same DW lobes and intervening SS regions, albeit with quantitative shifts, while systematic finite-size analyses reveal only weak dependence on lattice size, with no evidence of phase separation, collectively attesting to the robustness of the predicted phase structure. Together, our results establish a comprehensive mean-field framework that unifies the SOC-driven finite-momentum condensation and the NN-interaction-induced density ordering within a single picture, offering a valuable benchmark for future experimental explorations of spin-orbit-coupled spinor gases in optical lattices.

DOI
10.1088/1572-9494/aeae12

Related papers

Magnetic supersolid phases of two-dimensional extended Bose–Hubbard model with spin–orbit coupling

Dong-Dong Pu, Ji-Guo wang, Ya-Fei Song +1 more

Abstract We investigate the quantum phases and phase transitions for spin–orbit coupled two-species bosons with nearest-neighbor (NN) interaction in a two-dimensional square lattice using inhomogeneous dynamical Guztwiller mean-field method. Under the effect of spin–orbit coupling and NN interaction, we uncover a rich variety of different magnetic supersolid (SS) phases. In the presence of intraspecies NN interaction, the phase diagram exhibits the phase-twisted double-checkerboard SS (PT-DCSS) and phase-striped double-checkerboard SS (PS-DCSS) phases. For both intra- and interspecies NN interactions, apart from the phase-twisted lattice SS (PT-LSS) and phase-striped lattice SS (PS-LSS) phases, some nontrivial SS phases with interesting properties occur. More importantly, we find that the emergences of these nontrivial SS phases are dependent of the interspecies on-site interaction. To further characterize the SS phases, we also discuss the spin-dependent momentum distributions and magnetic textures. The magnetic textures, such as antiferromagnetic, spiral and stripe orders are shown. Finally, we give the fully analytical insights into the numerical results.

arXiv:2307.15310•New Journal of Physics•Mar 27, 2024•4 citations

Magnetic quantum phases of spin-orbit-coupled anisotropic dipolar bosons in square lattices

Nitin Kaloya, Kuldeep Suthar

We examine the two-dimensional spin-orbit-coupled bosons in the presence of an anisotropic dipolar interaction in square lattices. The spin-orbit coupling leads to finite-momentum superfluid and supersolid states, while the nearest-neighbour interaction induces crystalline characteristics in the quantum phases of soft-core bosons. We employ site-decoupled Gutzwiller ansatz and mean-field decoupling theory to obtain the phase diagrams and investigate the effects of the tilt of magnetic dipoles with respect to the polarization axis. Our study reveals the intriguing quantum phase transition of checkerboard finite-momentum phase-twisted and phase-stripe states into their stripe counterparts at a magic tilt angle, at which the off-site interaction along one of the directions becomes zero. At smaller tilt angles, the checkerboard charge-density-wave phase intervened by two compressible finite-momentum phases, and at strong spin-orbit coupling strengths, the phase-twisted supersolid and superfluid phases emerge. At larger tilt angles, a transition between the striped order of phase-twisted states and phase-stripe states occurs. The inclusion of off-site inter-component correlation leads to density-correlated phases, lattice-induced supersolid, and ferromagnetic quantum phases. Our study highlights novel finite-momentum crystal phases of spin-orbit-coupled dipolar bosons and provides a parameter space to observe them in quantum gas experiments.

arXiv:2604.25694•Apr 28, 2026•0 citations

Superfluid–Mott-insulator transition in the spin-orbit-coupled Bose-Hubbard model

Ahmet Tuna Bolukbasi, M. Iskin

We consider a square optical lattice in two dimensions and study the effects of both the strength and symmetry of spin-orbit coupling and Zeeman field on the ground-state, i.e., Mott-insulator (MI) and superfluid (SF), phases and phase diagram, i.e., MI-SF phase-transition boundary, of the two-component Bose-Hubbard model. In particular, based on a variational Gutzwiller ansatz, our numerical calculations show that the spin-orbit-coupled SF phase is a nonuniform (twisted) one, with its phase (but not the magnitude) of the order parameter modulating from site to site. Fully analytical insights into the numerical results are also given.

arXiv:1401.0527•Physical Review A•Apr 4, 2014•15 citations

Interaction-driven exotic quantum phases in spin-orbit-coupled spin-1 bosons

J. H. Pixley, Stefan S. Natu, Ian B. Spielman +1 more

We study the interplay between large-spin, spin-orbit coupling, and superfluidity for bosons in a two-dimensional optical lattice, focusing on the spin-1 spin-orbit-coupled system recently realized at the Joint Quantum Institute [Campbell et al., arXiv:1501.05984]. We find a rich quantum phase diagram where, in addition to the conventional phases---superfluid and insulator---contained in the spin-1 Bose-Hubbard model, there are new lattice symmetry breaking phases. For weak interactions, the interplay between two length scales, the lattice momentum and the spin-orbit wave vector, induce a phase transition from a uniform superfluid to a phase where bosons simultaneously condense at the center and edge of the Brillouin zone at a nonzero spin-orbit strength. This state is characterized by spin-density-wave order, which arises from the spin-1 nature of the system. Interactions suppress spin-density-wave order, and favor a superfluid only at the Brillouin zone edge. This state has spatially oscillating mean-field order parameters, but a homogeneous density. We show that the spin-density-wave superfluid phase survives in a two-dimensional harmonic trap, and thus establish that our results are directly applicable to experiments on $^{87}\mathrm{Rb},\phantom{\rule{0.16em}{0ex}}^{7}\mathrm{Li}$, and $^{41}\mathrm{K}$.

arXiv:1509.00005•Physical review. B./Physical review. B•Feb 1, 2016•14 citations

Thermal transitions of the modulated superfluid for spin-orbit coupled correlated bosons in an optical lattice

Arijit Dutta, Abhishek Joshi, K. Sengupta +1 more

We investigate the thermal physics of a Bose-Hubbard model with Rashba spin-orbit coupling starting from a strong coupling mean-field ground state. The essential role of the spin-orbit coupling $\left(\ensuremath{\gamma}\right)$ is to promote condensation of the bosons at a finite wave vector ${\mathbit{k}}_{0}$. We find that the bosons display either homogeneous or phase-twisted or orbital ordered superfluid phases, depending on $\ensuremath{\gamma}$ and the interspecies interaction strength $\left(\ensuremath{\lambda}\right)$. We show that an increase of $\ensuremath{\gamma}$ leads to suppression of the critical interaction ${U}_{c}$ for the superfluid to Mott insulator transition in the ground state and a reduction of the ${T}_{c}$ for superfluid to Bose-liquid transition at a fixed interaction strength. We capture the thermal broadening in the momentum distribution function, and the real space profiles of the thermally disordered magnetic textures, including their homogenization for $T\ensuremath{\gtrsim}{T}_{c}$. We provide a Landau theory based description of the ground state phase boundaries and thermal transition scales and discuss experiments which can test our theory.

arXiv:1901.10672•Physical review. B./Physical review. B•May 14, 2019•3 citations

Two-Component Spin-Orbit Coupled Ultracold Atoms in the Weak and Strong Coupling Regimes

Even Thingstad

Motivated by recent experimental advances, we study two-component spin-orbit coupled ultracold bosonic atoms in two dimensions on a square optical lattice. Using a Bose-Hubbard model with spin-conserving and non-spin-conserving nearest neighbour hoppings and spin-dependent on-site density-density interaction, our goal is to characterize phase separation and spin structure in the weakly interacting and deep Mott regimes. \nFor the weakly coupled regime, we decouple interactions through a real space uniform density mean field theory. At zero temperature, this gives an analytic condition for the phase separation transition driven by inter- relative to intracomponent interaction. Solving the self-consistent equations at finite temperature reveals entropic remixing in the phase separated regime and a more surprising entropy driven phase separation in the mixed regime. This is a consequence of complex interplay between interaction and spin-orbit coupling, and can be explained through the effect of component imbalance on the effective single-particle dispersion relation. We also provide an alternate explanation based on thermal occupation of eigenstates with a characteristic imbalance.\nIn the strongly interacting Mott regime, we derive an effective spin Hamiltonian describing the magnetic phases of the Mott insulator. The competition between anisotropic {Heisenberg} and Dzyaloshinskii-Moriya interactions gives rise to various ferromagnetic, antiferromagnetic, spiral, stripe, vortex, and skyrmion phases. On basis of classical Monte-Carlo simulations in the literature, we reconstruct the phase diagram with a classical variational approach, while magnon excitation spectra and quantum fluctuations are calculated with Holstein-Primakoff transformation and subsequent spin wave expansion. The analysis shows that states with ferromagnetic or antiferromagnetic ordering of boson species are protected against thermal fluctuations by a gap, and well described by classical states. States with equal superposition of boson species at each lattice site are subject to relatively large quantum fluctuations, which may cause breakdown of the states within their classical parameter space regions. The dispersion relations are gapless and linear around the minima to lowest order in the spin wave expansion.

•Jan 1, 2017•0 citations
Abstract The interplay between spin-orbit coupling (SOC) and nearest-neighbor (NN) repulsion in optical lattices provides a fertile ground for realizing exotic quantum phases that simultaneously host finite-momentum condensation and spontaneous density modulation. We address this interplay for spin-1 bosons in a two-dimensional square lattice with Rashba SOC and NN interactions, employing the single-site Gutzwiller mean-field (SGMF) method as our primary tool and the 2×22\times22×2 cluster Gutzwiller mean-field (CGMF) approach as a systematic check of short-range correlation effects. Our central finding is that SOC fundamentally reconstructs the single-particle band structure, shifting the lowest-band minimum from zero to finite momenta with increasing SOC strength. This reconstruction underpins a cascade of modulated superfluid (SF) phases-stripe, square, twist, and checkerboard-whose condensate textures are dictated predominantly by SOC. The addition of NN repulsion naturally favors real-space density ordering; the competition and cooperation between this density order and SOC-generated phase textures then stabilize a family of supersolid (SS) phases that mirror the same four modulated patterns, in which finite-momentum condensate and density-wave orders coexist. To complement the numerical phase diagrams, we derive semi-analytical phase boundaries for both the Mott-insulator (MI)-SF and density-wave (DW)-SS transitions using second-order perturbation theory. These expressions not only reproduce the overall trends of the SGMF results but also provide a transparent physical picture of the underlying instability mechanisms. Importantly, the representative CGMF calculations retain the same DW lobes and intervening SS regions, albeit with quantitative shifts, while systematic finite-size analyses reveal only weak dependence on lattice size, with no evidence of phase separation, collectively attesting to the robustness of the predicted phase structure. Together, our results establish a comprehensive mean-field framework that unifies the SOC-driven finite-momentum condensation and the NN-interaction-induced density ordering within a single picture, offering a valuable benchmark for future experimental explorations of spin-orbit-coupled spinor gases in optical lattices.
Abstract We investigate the quantum phases and phase transitions for spin–orbit coupled two-species bosons with nearest-neighbor (NN) interaction in a two-dimensional square lattice using inhomogeneous dynamical Guztwiller mean-field method. Under the effect of spin–orbit coupling and NN interaction, we uncover a rich variety of different magnetic supersolid (SS) phases. In the presence of intraspecies NN interaction, the phase diagram exhibits the phase-twisted double-checkerboard SS (PT-DCSS) and phase-striped double-checkerboard SS (PS-DCSS) phases. For both intra- and interspecies NN interactions, apart from the phase-twisted lattice SS (PT-LSS) and phase-striped lattice SS (PS-LSS) phases, some nontrivial SS phases with interesting properties occur. More importantly, we find that the emergences of these nontrivial SS phases are dependent of the interspecies on-site interaction. To further characterize the SS phases, we also discuss the spin-dependent momentum distributions and magnetic textures. The magnetic textures, such as antiferromagnetic, spiral and stripe orders are shown. Finally, we give the fully analytical insights into the numerical results.
We examine the two-dimensional spin-orbit-coupled bosons in the presence of an anisotropic dipolar interaction in square lattices. The spin-orbit coupling leads to finite-momentum superfluid and supersolid states, while the nearest-neighbour interaction induces crystalline characteristics in the quantum phases of soft-core bosons. We employ site-decoupled Gutzwiller ansatz and mean-field decoupling theory to obtain the phase diagrams and investigate the effects of the tilt of magnetic dipoles with respect to the polarization axis. Our study reveals the intriguing quantum phase transition of checkerboard finite-momentum phase-twisted and phase-stripe states into their stripe counterparts at a magic tilt angle, at which the off-site interaction along one of the directions becomes zero. At smaller tilt angles, the checkerboard charge-density-wave phase intervened by two compressible finite-momentum phases, and at strong spin-orbit coupling strengths, the phase-twisted supersolid and superfluid phases emerge. At larger tilt angles, a transition between the striped order of phase-twisted states and phase-stripe states occurs. The inclusion of off-site inter-component correlation leads to density-correlated phases, lattice-induced supersolid, and ferromagnetic quantum phases. Our study highlights novel finite-momentum crystal phases of spin-orbit-coupled dipolar bosons and provides a parameter space to observe them in quantum gas experiments.
We consider a square optical lattice in two dimensions and study the effects of both the strength and symmetry of spin-orbit coupling and Zeeman field on the ground-state, i.e., Mott-insulator (MI) and superfluid (SF), phases and phase diagram, i.e., MI-SF phase-transition boundary, of the two-component Bose-Hubbard model. In particular, based on a variational Gutzwiller ansatz, our numerical calculations show that the spin-orbit-coupled SF phase is a nonuniform (twisted) one, with its phase (but not the magnitude) of the order parameter modulating from site to site. Fully analytical insights into the numerical results are also given.
We study the interplay between large-spin, spin-orbit coupling, and superfluidity for bosons in a two-dimensional optical lattice, focusing on the spin-1 spin-orbit-coupled system recently realized at the Joint Quantum Institute [Campbell et al., arXiv:1501.05984]. We find a rich quantum phase diagram where, in addition to the conventional phases---superfluid and insulator---contained in the spin-1 Bose-Hubbard model, there are new lattice symmetry breaking phases. For weak interactions, the interplay between two length scales, the lattice momentum and the spin-orbit wave vector, induce a phase transition from a uniform superfluid to a phase where bosons simultaneously condense at the center and edge of the Brillouin zone at a nonzero spin-orbit strength. This state is characterized by spin-density-wave order, which arises from the spin-1 nature of the system. Interactions suppress spin-density-wave order, and favor a superfluid only at the Brillouin zone edge. This state has spatially oscillating mean-field order parameters, but a homogeneous density. We show that the spin-density-wave superfluid phase survives in a two-dimensional harmonic trap, and thus establish that our results are directly applicable to experiments on 87Rb,7Li^{87}\mathrm{Rb},\phantom{\rule{0.16em}{0ex}}^{7}\mathrm{Li}87Rb,7Li, and 41K^{41}\mathrm{K}41K.
We investigate the thermal physics of a Bose-Hubbard model with Rashba spin-orbit coupling starting from a strong coupling mean-field ground state. The essential role of the spin-orbit coupling $\left(\ensuremath{\gamma}\right)$ is to promote condensation of the bosons at a finite wave vector ${\mathbit{k}}_{0}$. We find that the bosons display either homogeneous or phase-twisted or orbital ordered superfluid phases, depending on $\ensuremath{\gamma}$ and the interspecies interaction strength $\left(\ensuremath{\lambda}\right)$. We show that an increase of $\ensuremath{\gamma}$ leads to suppression of the critical interaction Uc{U}_{c}Uc​ for the superfluid to Mott insulator transition in the ground state and a reduction of the Tc{T}_{c}Tc​ for superfluid to Bose-liquid transition at a fixed interaction strength. We capture the thermal broadening in the momentum distribution function, and the real space profiles of the thermally disordered magnetic textures, including their homogenization for $T\ensuremath{\gtrsim}{T}_{c}$. We provide a Landau theory based description of the ground state phase boundaries and thermal transition scales and discuss experiments which can test our theory.
Motivated by recent experimental advances, we study two-component spin-orbit coupled ultracold bosonic atoms in two dimensions on a square optical lattice. Using a Bose-Hubbard model with spin-conserving and non-spin-conserving nearest neighbour hoppings and spin-dependent on-site density-density interaction, our goal is to characterize phase separation and spin structure in the weakly interacting and deep Mott regimes. \nFor the weakly coupled regime, we decouple interactions through a real space uniform density mean field theory. At zero temperature, this gives an analytic condition for the phase separation transition driven by inter- relative to intracomponent interaction. Solving the self-consistent equations at finite temperature reveals entropic remixing in the phase separated regime and a more surprising entropy driven phase separation in the mixed regime. This is a consequence of complex interplay between interaction and spin-orbit coupling, and can be explained through the effect of component imbalance on the effective single-particle dispersion relation. We also provide an alternate explanation based on thermal occupation of eigenstates with a characteristic imbalance.\nIn the strongly interacting Mott regime, we derive an effective spin Hamiltonian describing the magnetic phases of the Mott insulator. The competition between anisotropic {Heisenberg} and Dzyaloshinskii-Moriya interactions gives rise to various ferromagnetic, antiferromagnetic, spiral, stripe, vortex, and skyrmion phases. On basis of classical Monte-Carlo simulations in the literature, we reconstruct the phase diagram with a classical variational approach, while magnon excitation spectra and quantum fluctuations are calculated with Holstein-Primakoff transformation and subsequent spin wave expansion. The analysis shows that states with ferromagnetic or antiferromagnetic ordering of boson species are protected against thermal fluctuations by a gap, and well described by classical states. States with equal superposition of boson species at each lattice site are subject to relatively large quantum fluctuations, which may cause breakdown of the states within their classical parameter space regions. The dispersion relations are gapless and linear around the minima to lowest order in the spin wave expansion.