arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2502.17876cond-mat.dis-nn
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准周期网络模型中精确运动边的确定

Exact mobility edges in quasiperiodic network models with slowly varying potentials

University of Science and Technology of China(中国科学技术大学);Central South University(中南大学)

Hai-Tao Hu, Yang Chen, Xiaoshui Lin, Ai-Min Guo, Zijing Lin, Ming Gong

AI总结:

本文提出了一种新的准周期网络模型,通过有效哈密顿量方法精确确定了运动边,适用于复杂几何和非厄米特征的模型,并展示了其在光波导中的实现可能性。

摘要:

准周期模型是探索低维系统中安德森过渡的重要物理平台,但精确运动边(MEs)通常难以通过解析方法确定。截至目前,只有少数模型的MEs可以被精确确定。在本文中,我们提出了一类新的网络模型,其特点是具有准周期性缓慢变化的势能,并且不存在隐藏的自对偶性,我们精确确定了这些模型的MEs。我们以具有缓慢变化势能的马赛克模型为例,说明这一结果,并通过有效哈密顿量推导其MEs。在该方法中,我们可以通过积分出周期性站点,得到一个具有能量依赖势能$g(E)V$和有效本征能量$f(E)$的有效哈密顿量,这直接导致MEs出现在$f(E) = \pm(2t^κ\pm g(E)V)$,其中$κ∈\mathbb{Z}^+$。掌握这一思想后,我们将该方法推广到更多的准周期网络模型中,包括那些具有更加复杂几何结构和非厄米特征的模型。最后,我们提出利用光波导实现这些模型,并展示即使在小物理系统中(约有$L = 50 - 100$个晶格点)也可以观察到安德森过渡。我们的结果为理解并实现实验中的精确MEs提供了关键见解。

英文摘要:

Quasiperiodic models are important physical platforms to explore Anderson transitions in low dimensional systems, yet the exact mobility edges (MEs) are generally hard to be determined analytically. To date, the MEs in only a few models can be determined exactly. In this manuscript, we propose a new class of network models characterized by quasiperiodic slowly varying potentials and the absence of hidden self-duality, and exactly determine their MEs. We take the mosaic models with slowly varying potentials as examples to illustrate this result and derive its MEs from the effective Hamiltonian. In this method, we can integrate out the periodic sites to obtain an effective Hamiltonian with energy-dependent potentials $g(E)V$ and effective eigenenergy $f(E)$, which directly yields the MEs at $f(E) = \pm(2t^κ\pm g(E)V)$, where $κ\in \mathbb{Z}^+$. With this idea in hand, we then generalize our method to more quasiperiodic network models, including those with much more complicated geometries and non-Hermitian features. Finally, we propose the realization of these models using optical waveguides and show that the Anderson transition can be observed even in small physical systems (with lattice sites about $L = 50 - 100$). Our results provide some key insights into the understanding and realization of exact MEs in experiments.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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