成矿量子临界性：带隙相之间跃迁处的费米面成核
Metallogenic quantum criticality: Fermi surface nucleation at transitions between gapped phases
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中文总结 AI 辅助
本文提出成矿量子临界点（MGQCP）概念，构建其有效场论，发现带隙相跃迁处可出现费米面，为莫尔材料临界现象研究提供新方向。
中文摘要 AI 辅助
相互作用多体系统中的连续量子相变展现出普适现象，这些现象在很大程度上不依赖于微观细节。从伊辛模型的磁性跃迁等典型例子中提炼出的一个组织原则是，带隙相之间跃迁的低能物理由尺度不变量子场论支配，该理论在动量空间的孤立点处具有无隙自由度。本文中，我们表明这一原则可能以一种极端方式失效：在分隔两个完全带隙绝缘体的量子临界点处，整个无隙费米面可以出现。这些奇异的量子相变被命名为“成矿量子临界点（metallogenic quantum critical points, MGQCP）”。我们为不同分数量子陈绝缘体之间的MGQCP构造了一族可控有效场论，并提出周期调制的量子霍尔双层作为最小微观模型。该临界理论展现出不同寻常的混合物理特征：输运和压缩率遵循与共形场论兼容的标度律，而电子谱函数在费米动量处呈现幂律非解析性，这是非费米液体金属的特征。我们讨论了MGQCP概念如何为具有可调陈带的莫尔材料中的临界现象提供新的视角。更广泛地说，我们的结果指向一类更宽泛的量子临界现象，其中尽管在相邻两相中均不存在，无隙激发的延展流形仍在动量空间中出现。
英文摘要
Continuous quantum phase transitions in interacting many-body systems exhibit universal phenomena that are largely independent of microscopic details. An organizing principle distilled from canonical examples such as the magnetic transition in Ising models is that the low-energy physics of transitions between gapped phases is governed by scale-invariant quantum field theories with gapless degrees of freedom at isolated points in momentum space. In this paper, we show that this principle can fail in a radical way: an entire gapless Fermi surface can emerge at a quantum critical point separating two fully gapped insulators. These exotic phase transitions are dubbed \textit{metallogenic quantum critical points} (MGQCP). We construct a controlled family of effective field theories for MGQCPs between distinct fractional Chern insulators and propose a periodically modulated quantum Hall bilayer as a minimal microscopic setting. The critical theory exhibits an unusual mixture of physical signatures: while transport and compressibility follow scaling laws compatible with a conformal field theory, the electron spectral function develops a power-law non-analyticity at the Fermi momentum, characteristic of non-Fermi-liquid metals. We discuss how the concept of MGQCP may shed new light on critical phenomena in moire materials with tunable Chern bands. More generally, our results point to a broader class of quantum critical phenomena in which extended manifolds of gapless excitations emerge in momentum space despite being absent in both neighboring phases.
