Phase Diagrams of Antiferromagnetic Spin-1 Bosons on Square Optical Lattice with the Quadratic Zeeman Effect

Abstract

We study the quadratic Zeeman effect (QZE) in a system of antiferromagnetic spin-1 bosons on a square lattice and derive the ground-state phase diagrams by means of quantum Monte Carlo simulations and mean field treatment. The QZE imbalances the populations of the magnetic sublevels $\sigma =\pm 1$ and $\sigma =0$, and therefore affects the magnetic and mobility properties of the phases. Both methods show that the tip of the even Mott lobes, stabilized by singlet state, is destroyed when turning on the QZE, thus leaving the space to the superfluid phase. Contrariwise, the tips of odd Mott lobes remain unaffected. Therefore, the Mott-superfluid transition with even filling strongly depends on the strength of the QZE, and we show that the QZE can act as a control parameter for this transition at fixed hopping. Using quantum Monte Carlo simulations, we elucidate the nature of the phase transitions and examine in detail the nematic order: the first-order Mott-superfluid transition with even filling observed in the absence of QZE becomes second order for weak QZE, in contradistinction to our mean-field results which predict a first-order transition in a larger range of QZE. Furthermore, a spin nematic order with director along the $z$ axis is found in the odd Mott lobes and in the superfluid phase for energetically favored $\sigma =\pm 1$ states. In the superfluid phase with even filling, the $xy$ components of the nematic director remain finite only for moderate QZE.

14 pages, 18 figures

References in corpus (24)

• Many-Body Physics with Ultracold Gases
• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Squeezing and entanglement in a Bose-Einstein condensate
• Tuning the scattering length with an optically induced Feshbach resonance
• Evidence for Superfluidity of Ultracold Fermions in an Optical Lattice
• Monte Carlo study of two-dimensional Bose-Hubbard model
• Spontaneously modulated spin textures in a dipolar spinor Bose-Einstein condensate
• Spinor Dynamics in an Antiferromagnetic Spin-1 Condensate
• Quantum Phase Transitions and Continuous Observation of Spinor Dynamics in an Antiferromagnetic Condensate
• Phase diagram of spin-1 bosons on one-dimensional lattices
• Controlling and Detecting Spin Correlations of Ultracold Atoms in Optical lattices
• Phases and Transitions in the Spin-1 Bose-Hubbard Model: Systematics of a Mean-field Theory
• The Stochastic Green Function (SGF) algorithm
• Directed update for the Stochastic Green Function algorithm
• Spin-1 bosons with coupled ground states in optical lattices
• Magnetic and Superfluid Transitions in the d=1 Spin-1 Boson Hubbard Model
• Antiferromagnetic spinor condensates in a two-dimensional optical lattice
• Mapping the phase diagram of spinor condensates via adiabatic quantum phase transitions
• First- and second-order superfluid--Mott-insulator phase transitions of spin-1 bosons with coupled ground states in optical lattices
• Ground States of the Spin-1 Bose-Hubbard Model
• Spinful bosons in an optical lattice
• Mott Transition and Spin Structures of Spin-1 Bosons in Two-Dimensional Optical Lattice at Unit Filling
• Feshbach-Stabilized Insulator of Bosons in Optical Lattices
• Thermometry of bosonic mixtures in Optical Lattices via Demixing

Cited by in corpus (4)

• Spin Entanglement and Magnetic Competition via Long-range Interactions in Spinor Quantum Optical Lattices
• Phase diagrams and multistep condensations of spin-1 bosonic gases in optical lattices
• Magnetic Phase Transition in the Ground-State Phase Diagram of Binary Bose Gases in Optical Lattices
• Stability of supercurrents in a superfluid phase of spin-1 bosons in an optical lattice