We study the three-dimensional bosonic t-J model, that is, the t-J model of "bosonic electrons" at finite temperatures. This model describes a system of an isotropic antiferromagnet with doped bosonic holes and is closely related to systems of two-component bosons in an optical lattice. The bosonic "electron" operator B xσ at the site x with a two-component spin σ (=1,2) is treated as a hard-core boson operator and represented by a composite of two slave particles: a spinon described by a Schwinger boson (CP 1 boson) z xσ and a holon described by a hard-core-boson field φ x as B xσ = φ † x z xσ . By means of Monte Carlo simulations of this bosonic t-J model, we study its phase structure and the possible phenomena like appearance of antiferromagnetic long-range order, Bose-Einstein condensation, phase separation, etc. Obtained results show that the bosonic t-J model has a phase diagram that suggests some interesting implications for high-temperature superconducting materials.

We study the three-dimensional bosonic t-J model, i.e., the t-J model of "bosonic electrons," at finite temperatures. This model describes the s = 1 2 Heisenberg spin model with the anisotropic exchange coupling J ⊥ = αJ z and doped bosonic holes, which is an effective system of the Bose-Hubbard model with strong repulsions. The bosonic "electron" operator B rσ at the site r with a two-component (pseudo)spin σ (= 1,2) is treated as a hard-core boson operator. By means of Monte Carlo simulations, we study its finite-temperature phase structure including the α dependence, the possible phenomena-like appearance of checkerboard long-range order, supercounterflow, superfluidity, phase separation, etc. The obtained results, which clarify the relation between various phases, may be taken as predictions about experiments of two-component cold bosonic atoms in a cubic optical lattice.

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