Notable non-Fermi liquid and quantum critical behaviors are observed in rare-earth metallic systems with non-Kramers local moments supporting a number of different multipolar moments. A prominent example is $\text{Pr(Ti,V)}_{2}\text{Al}_{20}$, where the non-Kramers doublet of the $\text{Pr}^{3+}$ ion allows quadrupolar and octupolar moments, but lacks a dipolar moment. Previous theoretical studies show that a single impurity Kondo problem with such an unusual local moment leads to novel non-Fermi liquid states. In this work, we investigate possible quantum critical behaviors arising from the competition between non-Fermi liquid states and multipolar-ordered phases induced by the RKKY interaction. We consider a local version of the corresponding Kondo lattice model, namely the Bose-Fermi Kondo model. Here, the multipolar local moments are coupled to fermionic and bosonic bath degrees of freedom representing the multipolar Kondo effect and RKKY interactions. Using a perturbative renormalization group (RG) study up to two loop order, we find critical points between non-Fermi liquid Kondo fixed points and a quadrupolar ordered fixed point. The critical points describe quantum critical behaviors at the corresponding phase transitions and can be distinguished by higher order corrections in the octupolar susceptibility that can be measured by ultrasound experiments. Our results imply the existence of a rich expansion of the phases and quantum critical behaviors in multipolar heavy fermion systems.
Landau theory of multipolar orders in Pr(TM)$_2$X$_{20}$ Kondo materials
一系列Pr（TM）$_2$ X $_{20}$（TM=Ti，V，Rh，Ir，X=Al，Zn）Kondo材料，在金刚石晶格上含有非Kramers Pr $^{3+}$ $4f^2$矩，已被证明表现出缠结有序，如四极有序和超导性。受这些实验的启发，我们提出并研究了一个多极序的朗道理论来捕捉相图及其场依赖性。在零磁场中，我们证明了不同的四极态，或者四极和八极有序的共存，可能导致多重对称性破缺的基态。在加热时，这些状态可以经历两步热转变成对称顺磁相，在中间相部分恢复被破坏的对称性。对于非零磁场，我们表明这些热相变的演变强烈依赖于磁场的方向，由于时钟各向异性项的自由能。我们的发现揭示了Pr（TM）$_2$ Al $_{20}$材料的实验结果。我们提出了进一步的实验测试，以区分纯粹的四极订单共存的四极八极订单。
Evolution of non-Kramers Doublets in Magnetic Field PrNi$_2$Cd$_{20}$ and PrPd$_2$Cd$_{20}$
基于镨的1-2-20笼化合物Pr $T_2X_{20}$（$T$通常是Ti、V、Nb、Ru、Rh、Ir;并且$X$是Al、Zn或Cd）提供了另一个平台来研究从拓扑和磁序到非常规多极序和超导性的物质的非平凡电子状态。本文报道了两种Pr基1-2-20材料PrNi $_2$ Cd $_{20}$和PrPd $_2$ Cd $_{20}$的电子热容的测量结果。我们发现Pr的$4f^2$价态的最低能量多重态是$Γ_3$非Kramers双重态，第一激发三重态被假定为磁性$Γ_5$ .通过分析基态和第一激发单重态之间的能量分裂对外部磁场的依赖关系，我们发现，与PrNi $_2$ Cd $_{20}$不同，PrPd $_2$ Cd $_{20}$中对应于肖特基异常的热容的最大值对外部磁场具有明显的线性依赖性，在较高的磁场值下.这种效应与场致磁偶极矩之间的交换相互作用有关。
Large positive correlation between the effective electron mass and the multipolar fluctuation in the heavy-fermion metal Ce$_{1-x}$La$_x$B$_6$
在过去的几十年里，研究人员一直对多极有序现象感兴趣，同时在重费米子近藤系统Ce $_{1-x}$ La $_{x}$ B $_6$中寻找相关的量子临界性。然而，临界现象引起的取代水平（$x$），温度（$T$），和磁场（$B$）的了解甚少，尽管收集了大量的实验结果。本文给出了Ce $_{1-x}$ La $_x$ B $_6$（$\mathbf{B}\parallel[110]$）的$T$ - $B$、$x$-$T$和$x$ -$B$相图.这些都是通过分析热容量，磁热效应（MCE）和弹性中子散射。索末菲系数$γ_0$的急剧增加，这是估计从热容下降到0.05 K，观察到与增加$x$。通过在Ce $_{1-x}$ La $_x$ B $_6$中首次分析MCE，绘制了精确的$T$-$B$相图，其中包含不可预见的高熵区域。$x$ - $B$相图支持在$x>0.75$处存在QCP，通过相同的分析获得。相图的详细解释强烈表明波动多极子和有效电子质量之间的正相关性。
Quantum criticality and emergent orders in the spin-1 bilinear-biquadratic-Kitaev chain
National Laboratory of Solid State Microstructures（固体微结构物理国家重点实验室）；Department of Physics, Nanjing University（南京大学物理学院）；Suzhou Institute for Advanced Research, University of Science and Technology of China（中国科学技术大学苏州高等研究院）；School of Artificial Intelligence and Data Science, University of Science and Technology of China（中国科学技术大学人工智能与数据科学学院）；College of Physics, Nanjing University of Aeronautics and Astronautics（南京航空航天大学物理学院）；Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT（工业和信息化部航空航天信息材料与物理重点实验室）；Collaborative Innovation Center of Advanced Microstructures, Nanjing University（南京大学先进微结构协同创新中心）
Succession of Ising criticality and its threshold in critical quantum Ising model subject to $X+ZZ$ decoherence
Graduate School of Engineering science, Akita University（秋田大学工学研究科）；Department of Physics, College of Humanities and Sciences, Nihon University（日本大学文理学部物理学系）；Department of Applied Physics, Nagoya Institute of Technology（名古屋工业大学应用物理系）
Decoherence-induced self-dual criticality in topological states of matter
The Hong Kong University of Science and Technology (Guangzhou)（香港科技大学（广州））；University of Geneva（日内瓦大学）；University of Cologne（科隆大学）；University of California, Santa Barbara（加州大学圣塔芭芭拉分校）
Measurement-induced criticality for non-Abelian anyons: The monitored golden chain
The Hong Kong University of Science and Technology (Guangzhou)（香港科技大学（广州））；Institute for Theoretical Physics, University of Cologne（科隆大学理论物理研究所）；Department of Theoretical Physics, University of Geneva（日内瓦大学理论物理系）；Geneva Quantum Center, University of Geneva（日内瓦大学日内瓦量子中心）；Department of Physics, University of California, Santa Barbara（加州大学圣塔芭芭拉分校物理系）
Extracting Boundary Conformal Data from Periodic Non-Hermitian Critical Chains
Institute for Solid State Physics, University of Tokyo（东京大学固体物理研究所）；Mathematical Sciences Institute, The Australian National University（澳大利亚国立大学数学科学学院）
Boundary critical phenomena in the quantum Ashkin-Teller model
University of Tokyo（东京大学）；Delft University of Technology（代尔夫特理工大学）；National Taiwan University（台湾大学）；National Tsing Hua University（国立清华大学）；The University of Tokyo（东京大学）
