On-site pairing and microscopic inhomogeneneity in confined lattice fermion systems
On-site pairing and microscopic inhomogeneneity in confined lattice fermion systems
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DOI：
10.1103/physreva.74.053621
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发表时间：
2006-12
影响因子：
2.9
通讯作者：
M. Machida;S. Yamada;Y. Ohashi;H. Matsumoto
中科院分区：
文献类型：
--
作者：
M. Machida;S. Yamada;Y. Ohashi;H. Matsumoto
为了探索原子费米气体加载在光学晶格上的普遍特征，我们系统地研究了具有谐波势阱的一维和二维吸引Hubbard模型的粒子密度分布。利用精确对角化方案和密度矩阵重整群技术，我们证明了在上述模型中普遍存在精细的非齐次之字形图案。理论和数值分析表明，这些结构源于紧密结合对之间的有效排斥相互作用和平移不变性的破坏。此外，还强调了二维模型中数值得到的模式是棋盘型的，这与最近在高t {sub c}铜超导体涡旋核中观察到的结果非常相似。
In order to explore a universal feature of atomic Fermi gases loaded on optical lattices, we make a systematic study of the particle density profile for one- and two-dimensional attractive Hubbard models with harmonic potential wells. Using the exact diagonalization scheme and the density-matrix renormalization group technique, we show that fine inhomogeneous zigzag patterns universally emerge in the above models. Theoretical and numerical analyses suggest that these structures originate from an effective repulsive interaction between tightly bound pairs and a breakdown of translational invariance. Furthermore, it is emphasized that the pattern obtained numerically in the two-dimensional model is the checkerboard type, which is very similar to results recently observed in a vortex core of high-T{sub c} cuprate superconductor.