Superfluid-Mott insulator transition of spin-1 bosons in an optical lattice
Superfluid-Mott insulator transition of spin-1 bosons in an optical lattice
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DOI：
10.1103/physreva.70.043628
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发表时间：
2002-09
影响因子：
2.9
通讯作者：
S. Tsuchiya;S. Kurihara;T. Kimura
中科院分区：
文献类型：
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作者：
S. Tsuchiya;S. Kurihara;T. Kimura
研究了光学晶格中反铁磁相互作用的自旋-1玻色子的超流体-莫特绝缘子跃迁。从自旋为1的玻色子的玻色-哈伯德紧密结合模型出发，通过平均场近似得到了零温度相图。我们发现，在t=0的极限下，每个位点有偶数个原子的MI相是自旋单重态，而每个位点有奇数个原子的MI相在每个位点都有自旋1，其中t是跳跃矩阵元素。我们还证明了超流体相是极性态，就像在谐波阱中自旋为1的玻色凝聚体一样。研究发现，当每个位点的原子数相等时，由于单线态对的形成，MI相对SF-MI跃迁具有很强的稳定性。我们推导了每位有一个原子的MI相的有效自旋哈密顿量，并简要讨论了MI相的自旋顺序。
We study the superfluid-Mott insulator (SF-MI) transition of spin-1 bosons interacting antiferromagnetically in an optical lattice. Starting from a Bose-Hubbard tight-binding model for spin-1 bosons, we obtain the zero-temperature phase diagram by a mean-field approximation. We find that the MI phase with an even number of atoms per site is a spin singlet state, while the MI phase with an odd number of atoms per site has spin 1 at each site in the limit of t=0, where t is the hopping matrix element. We also show that the superfluid phase is a polar state as in the case for a spin-1 Bose condensate in a harmonic trap. It is found that the MI phase is strongly stabilized against the SF-MI transition when the number of atoms per site is even, due to the formation of singlet pairs. We derive the effective spin Hamiltonian for the MI phase with one atom per site and briefly discuss the spin order in the MI phase.