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arXiv 2004.03506cond-mat.quant-gas
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三维Anderson-哈伯德模型中的两体迁移率边:分子与散射态

Two-body mobility edge in the Anderson-Hubbard model in three dimensions: Molecular versus scattering states

Filippo Stellin, Giuliano Orso

摘要:

我们对无序诱导的金属-绝缘体跃迁的大部分定量理解都来自于简单的非相互作用紧束缚模型的数值研究,比如三维的安德森模型。一个重要的悬而未决的问题是安德森转变的命运在额外的哈伯德相互作用的强度$U$粒子之间的存在。基于大尺度数值方法,我们计算了两个全同玻色子或两个自旋分量相反的费米子系统的迁移率边的位置。由此产生的相图在相互作用-能量-无序空间中具有非常丰富和违反直觉的结构,具有多个金属相和绝缘相。我们表明,这种现象源于分子或散射的性质,在给定的能量$E$和无序强度$W$的对状态。对有效模型的无序平均态密度也进行了研究。最后,我们讨论了我们的研究结果正在进行的研究多体局域化的影响。

英文摘要:

Most of our quantitative understanding of disorder-induced metal-insulator transitions comes from numerical studies of simple noninteracting tight-binding models, like the Anderson model in three dimensions. An important outstanding problem is the fate of the Anderson transition in the presence of additional Hubbard interactions of strength $U$ between particles. Based on large-scale numerics, we compute the position of the mobility edge for a system of two identical bosons or two fermions with opposite spin components. The resulting phase diagram in the interaction-energy-disorder space possesses a remarkably rich and counterintuitive structure, with multiple metallic and insulating phases. We show that this phenomenon originates from the molecular or scattering-like nature of the pair states available at given energy $E$ and disorder strength $W$. The disorder-averaged density of states of the effective model for the pair is also investigated. Finally, we discuss the implications of our results for ongoing research on many-body localization.

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