发表机构
Chongqing University; Hangzhou Normal University; Institute of Physics, Chinese Academy of Sciences; School of Physical Sciences, University of Chinese Academy of Sciences（重庆大学; 杭州师范大学; 中国科学院物理研究所; 中国科学院大学物理科学学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过四杂质近藤模型区分集体与个体近藤屏蔽，发现集体屏蔽产生多级双通道近藤效应，个体屏蔽产生不稳定三通道效应，证实了集体屏蔽机制并展示了AUNRG方法的可扩展性。
AI 中文摘要
集体屏蔽已被提出作为多杂质和晶格近藤系统基本物理的基础。然而，如何建立这一图像并将其与个体（局域）近藤屏蔽区分开来，仍是一个重大挑战。最近发展的辅助浴数值重整化群（AUNRG）方法为解决这一问题提供了关键一步。将其应用于具有共享电子浴的$C_3$对称三杂质近藤（3IK）模型，揭示了在小近藤耦合$J_{\ m K}$下由团簇自旋自由度的集体屏蔽产生的完全屏蔽费米液体基态，以及在大$J_{\ m K}$下由局域杂质的个体（局域）屏蔽产生的基态。这里我们设计了一个四杂质近藤（4IK）模型，其中探针杂质仅与原始三个近藤杂质耦合，以探测屏蔽态的性质。我们表明，集体和个体近藤屏蔽分别产生涌现的多级、双通道近藤效应和不稳定的三通道近藤效应。这暗示了屏蔽态的特殊螺旋度结构，并证实了多杂质近藤系统中集体屏蔽的想法。我们的工作还表明，相同的辅助浴构造可以轻松扩展到具有额外杂质的模型，以探索具有涌现团簇自由度的新型多体量子态。
英文摘要
Collective screening has been proposed to underlie the basic physics of multi-impurity and lattice Kondo systems. But how to establish this picture and distinguish it from individual (local) Kondo screening remains a grand challenge. The recently developed auxiliary-bath numerical renormalization group (AUNRG) method provides a key step towards resolving this issue. Its application to the $C_3$-symmetric three-impurity Kondo (3IK) model with a shared electron bath reveals fully screened Fermi liquid ground states arising from collective screening of cluster spin degrees of freedom at small Kondo coupling $J_{\rm K}$ and individual (local) screening of local impurities at large $J_{\rm K}$. Here we design a four-impurity Kondo (4IK) model where the probe impurity couples only to the original three Kondo impurities to detect the nature of the screened states. We show that the collective and individual Kondo screenings give rise to emergent multi-stage, two-channel Kondo effect and unstable three-channel Kondo effect, respectively. This suggests a special helicity structure of the screened states and confirms the idea of collective screening in multi-impurity Kondo systems. Our work also demonstrates that the same auxiliary-bath construction can be readily extended to models with additional impurities to explore novel many-body quantum states with emergent cluster degrees of freedom.
Comments6 pages, 4 figures
