Quantum many-body simulations of the two-dimensional Fermi-Hubbard model in ultracold optical lattices
Quantum many-body simulations of the two-dimensional Fermi-Hubbard model in ultracold optical lattices
复制标题
超冷光学晶格中二维费米-哈伯德模型的量子多体模拟
DOI：
10.1103/physrevb.103.l041107
复制
发表时间：
2021-01-19
影响因子：
3.7
通讯作者：
Li, Wei
中科院分区：
文献类型：
--
作者：
Chen, Bin-Bin;Chen, Chuang;Li, Wei
了解相关电子的量子多体态是现代凝聚态物理学的主题之一。鉴于费米-哈伯德模型（相关电子的原型）最近已在超冷光学晶格中实现，因此非常需要控制数值方法来在掺杂时提供精确的有限温度结果，以便直接与实验进行比较。在这里，我们演示了指数张量重整化群 (XTRG) 算法 [Phys. Rev. X 8, 031082 (2018)]，辅以独立行列式量子蒙特卡罗 (DQMC)，为此目的提供了强大的工具组合。 XTRG 提供了对密度矩阵的全面而准确的访问，从而提供了各种自旋和电荷相关性，低至费米子隧道能量尺度的百分之几的前所未有的低温。我们在半填充和有限掺杂下观察到与超冷费米子测量的良好一致性，包括由于磁极化子的形成而导致的自旋相关性的符号反转行为，以及导致反矩的特殊聚束和反聚束行为的吸引空穴-双布朗和排斥空穴-空穴对。
Understanding quantum many-body states of correlated electrons is one main theme in modern condensed matter physics. Given that the Fermi-Hubbard model, the prototype of correlated electrons, has been recently realized in ultracold optical lattices, it is highly desirable to have controlled numerical methodology to provide precise finite-temperature results upon doping, to directly compare with experiments. Here, we demonstrate the exponential tensor renormalization group (XTRG) algorithm [Phys. Rev. X 8, 031082 (2018)], complemented with independent determinant quantum Monte Carlo (DQMC) offer a powerful combination of tools for this purpose. XTRG provides full and accurate access to the density matrix and thus various spin and charge correlations, down to unprecedented low temperature of few percents of the fermion tunneling energy scale. We observe excellent agreement with ultracold fermion measurements at both half-filling and finite-doping, including the sign-reversal behavior in spin correlations due to formation of magnetic polarons, and the attractive hole-doublon and repulsive hole-hole pairs that are responsible for the peculiar bunching and antibunching behavior of the antimoments.