Proposed formation and dynamical signature of a chiral Bose liquid in an optical lattice

Li, Xiaopeng; Paramekanti, Arun; Hemmerich, Andreas; Liu, W. Vincent

doi:10.1038/ncomms4205

Cited by 21 publications

(18 citation statements)

References 55 publications

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“…For the symmetric case with ρ ↑ = ρ ↓ , we have one single KT transition temperature, while for ρ ↑ = ρ ↓ there are two separate KT transitions at two distinct temperatures. The Ising transition associated with the chiral order is expected to occur slightly above higher superfluid transition, as observed in other studies of chiral superfluids [36]. In principle, a chiral spin state which has chiral spin order but no superfluidity could occur in a temperature window above superfluid transitions [36]; the exploration of such a remarkable bosonic chiral spin fluid is left for future studies.…”

Section: Methodsmentioning

confidence: 57%

“…Gρ σ , with G being the curvature of the bandstructure at K (see Methods) which determines the energy costs for phase twists. The chiral spin superfluid also breaks the discrete Z 2 symmetry, which is expected to be restored at a higher transition temperature [36], giving rise to a rich finite temperature phase diagram with an intermediate non-condensed chiral spin fluid phase separating the fully disordered and chiral spin superfluid phases.…”

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confidence: 99%

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Chiral magnetism and spontaneous spin Hall effect of interacting Bose superfluids

Natu

Paramekanti

et al. 2014

Nat Commun

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Recent experiments on ultracold atoms in optical lattices have synthesized a variety of tunable bands with degenerate double-well structures in momentum space. Such degeneracies in the single-particle spectrum strongly enhance quantum fluctuations, and often lead to exotic many-body ground states. Here we consider weakly interacting spinor Bose gases in such bands, and discover a universal quantum 'order by disorder' phenomenon which selects a novel superfluid with chiral spin order displaying remarkable properties such as spontaneous spin Hall effect and momentum space antiferromagnetism. For bosons in the excited Dirac band of a hexagonal lattice, such a state supports staggered spin loop currents in real space. We show that Bloch oscillations provide a powerful dynamical route to quantum state preparation of such a chiral spin superfluid. Our predictions can be readily tested in spin-resolved time-of-flight experiments.

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Section: Methodsmentioning

confidence: 57%

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confidence: 99%

Chiral magnetism and spontaneous spin Hall effect of interacting Bose superfluids

Natu

Paramekanti

et al. 2014

Nat Commun

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“…One cold atomic system which may host frustration in its groundstates, is the Hamburg experiment of Hemmerich [17,18]; degenerate s-and p-orbital atoms hybridize on neighboring sites in a superlattice. Also for this configuration the SF phase consists of vortices leading to a complex order parameter [19], and it was further argued that thermal fluctuations will induce a new phase, a chiral Bose liquid, in this model [20]. Nevertheless, much of the phase diagram of both the insulating and superfluid phase of the Hamburg set-up remains unexplored.…”

Section: Introductionmentioning

confidence: 93%

Magnetic phases of orbital bipartite optical lattices

Saugmann

Larson

2020

New J. Phys.

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In the Hamburg cold atom experiment with orbital states in an optical lattice, s-and p-orbital atomic states hybridize between neighboring sites. In this work we show how this alternation of sites hosting s-and p-orbital states gives rise to a plethora of different magnetic phases, quantum and classical. We focus on phases whose properties derive from frustration originating from a competition between nearest and next nearest neighboring exchange interactions. The physics of the Mott insulating phase with unit filling is described by an effective spin-1/2 Hamiltonian showing great similarities with the J 1 -J 2 model. Based on the knowledge of the J 1 -J 2 model, supported by numerical simulations, we discuss the possibility of a quantum spin liquid phase in the present optical lattice system. In the superfluid regime we consider the parameter regime where the s-orbital states can be adiabatically eliminated to give an effective model for the p-orbital atoms. At the mean-field level we derive a generalized classical XY model, and show that it may support maximum frustration. When quantum fluctuations can be disregarded, the ground state should be a spin glass. Figure 5. The energy of the ground state of the effective Hamiltonian for the Mott insulating phase (9). The energy is found for zero field h=0, and for = = J J J 0.9 X Y Z 1 1 1 , and as a function of J J Z Z 2 1 . The plot shows that an energy plateau is formed around = J J 0.5 Z Z 2 1 indicating the possibility that a there is an intermediate phase in between the Néel and striped phases.we see four distinct phases, the ferromagnetic phase (green), the Néel phase (white), the striped phase (dark pink), and the disordered phase (pink). In this (classical) limit all phase transitions are first first order. As we consider non-zero couplings = J J X Y 1 1 a fifth mean-field phase appears (light green/pink), this phase grows with increasing couplings = J J X Y 1 1 , and all PTs except for the one between the Néel phase and the ferromagnet phase, and the Néel and the new phase, appear to be second order. The new phase survives also for zero field, J Z =0, provided that = J J X Y 1 1 is large enough. At this mean-field level, the properties of the intermediate fifth phase is unknown. The dispersed dots are numerical errors for which the simulations are not capable of finding the true ground state.

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“…The artificial gauge fields, which allow one to generate spinorbit couplings and effective magnetic fields, opens a new path to explore quantum Hall effect and topological phases of matters. Our cluster Gutzwiller meanfield approach can also be extended to investigate the bosonic ladders in the presence of an artificial magnetic field [26,[57][58][59][60][61][62][63], such as the observation of chiral currents [57], the measurement of Chern number in Hofstadter bands [58,63], and the two-leg Bose-Hubbard ladder under a magnetic flux [26,61]. In addition, our cluster Gutzwiller mean-field approach may also use to explore the non-equilibrium dynamics of two coupled onedimensional Luttinger liquids [64] and the dynamical instability of interacting bosons in disordered lattices [65].…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Cluster Gutzwiller study of the Bose-Hubbard ladder: Ground-state phase diagram and many-body Landau-Zener dynamics

et al. 2015

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We present a cluster Gutzwiller mean-field study for ground states and time-evolution dynamics in the Bose-Hubbard ladder (BHL), which can be realized by loading Bose atoms in double-well optical lattices. In our cluster mean-field approach, we treat each double-well unit of two lattice sites as a coherent whole for composing the cluster Gutzwiller ansatz, which may remain some residual correlations in each two-site unit. For a unbiased BHL, in addition to conventional superfluid phase and integer Mott insulator phases, we find that there are exotic fractional insulator phases if the inter-chain tunneling is much stronger than the intra-chain one. The fractional insulator phases can not be found by using a conventional mean-field treatment based upon the single-site Gutzwiller ansatz. For a biased BHL, we find there appear single-atom tunneling and interaction blockade if the system is dominated by the interplay between the on-site interaction and the inter-chain bias. In the many-body Landau-Zener process, in which the inter-chain bias is linearly swept from negative to positive or vice versa, our numerical results are qualitatively consistent with the experimental observation [Nat. Phys. 7, 61 (2011)]. Our cluster bosonic Gutzwiller treatment is of promising perspectives in exploring exotic quantum phases and time-evolution dynamics of bosonic particles in superlattices.

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Proposed formation and dynamical signature of a chiral Bose liquid in an optical lattice

Cited by 21 publications

References 55 publications

Chiral magnetism and spontaneous spin Hall effect of interacting Bose superfluids

Chiral magnetism and spontaneous spin Hall effect of interacting Bose superfluids

Magnetic phases of orbital bipartite optical lattices

Cluster Gutzwiller study of the Bose-Hubbard ladder: Ground-state phase diagram and many-body Landau-Zener dynamics

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