SEARCH
Search Details
Kuniyoshi Shingo
| Faculty of Science Physics Electronic Condensed Matter Physics | Postdoctoral Fellow |
Researcher basic information
■ Degree■ URL
researchmap URLホームページURL■ Various IDs
Researcher number
- 01010082
Research Field
Research activity information
■ Awards■ Papers
- Theory of Many-Body Multipole Operators in Single-Centered Electron Systems: Two-Body Toroidal Monopoles in Spinless Orbitals
Shingo Kuniyoshi; Rikuto Oiwa; Satoru Hayami
Journal of the Physical Society of Japan, 11 Mar. 2026, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal, One-body multipole operators are defined as irreducible representations of rotational symmetry together with spatial-inversion and time-reversal symmetries, providing a systematic framework for classifying electronic internal degrees of freedom and for describing a wide variety of composite order parameters. While this formalism has been successfully established for the one-body operator space, a systematic classification of the many-body operator space, especially in interacting systems, remains an open challenge. In this paper, we extend the multipole formalism in the one-body operator space to the many-body operator space. By formulating fermionic creation and annihilation operators as spherical tensors and employing Clebsch-Gordan coupling combined with the exterior (Grassmann) algebra, we construct an irreducible decomposition of many-body operators that fully incorporates fermionic antisymmetrization. As a concrete application, we classify monopoles appearing in spinless many-body operators. In particular, we show that the electric toroidal monopole, a pseudoscalar breaking spatial-inversion symmetry, and the magnetic toroidal monopole, a time reversal-odd scalar, become active in spinless interacting many-body systems, although they are absent in the spinless one-body hybrid orbital space. - Uncovering hidden Fermi surface instabilities through visualizing unconventional quasiparticle interference in
B. R. M. Smith; Y. Fujisawa; P. Wu; T. Nakamura; N. Tomoda; S. Kuniyoshi; D. Ueta; R. Kobayashi; R. Okuma; K. Arai; K. Kuroda; C.-H. Hsu; G. Chang; C.-Y. Huang; H. Lin; Z. Y. Wang; T. Kondo; Y. Okada
Physical Review Materials, 09 Oct. 2024, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal - Heavy Fermion in Ferromagnetic Kondo Model with Integer Spin
Shingo Kuniyoshi; Ryousuke Shiina
New Physics: Sae Mulli, 31 Dec. 2023, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal - Emergent Heavy Local Fermi Liquid in the Ferromagnetic Kondo Model with Integer Impurity Spin
Shingo Kuniyoshi; Ryousuke Shiina
Journal of the Physical Society of Japan, 15 Sep. 2023, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal - Field-induced local Fermi-liquid states in the underscreened Kondo model for Eu compounds
Shingo Kuniyoshi; Ryousuke Shiina
SciPost Physics Proceedings, 06 Jun. 2023, [Peer-reviewed], [Lead author], [International Magazine]
International conference proceedings,
We have studied an underscreened Kondo model for the impurity spin
capturing the
characteristics of a nearly divalent Eu ion. By using the numerical renormalization group method, it is shown that an unusual heavy-fermion state is induced from the underscreened spin state when a weak crystal field is introduced. It is also found that the application of the magnetic field enhances the effective mass of the heavy fermions, reflecting the field-induced level crossing of the spin states. We will discuss the mechanism of these mass enhancements in terms of a realization of the two-stage Kondo effect.
- Valence Fluctuation and Magnetic–Nonmagnetic Crossover in Eu-based Impurity Anderson Model with Orbital-Dependent Hybridization
Shingo Kuniyoshi; Ryousuke Shiina
Proceedings of the 29th International Conference on Low Temperature Physics (LT29), Journal of the Physical Society of Japan, 22 May 2023, [Peer-reviewed], [Lead author], [International Magazine]
International conference proceedings - Anomalous Magnetic Moment Direction under Magnetic Anisotropy Originated from Crystalline Electric Field in van der Waals Compounds CeTe3 and CeTe2Se
Daichi Ueta; Riki Kobayashi; Hiroki Sawada; Yuki Iwata; Shin-ichiro Yano; Shingo Kuniyoshi; Yuita Fujisawa; Takatsugu Masuda; Yoshinori Okada; Shinichi Itoh
Journal of the Physical Society of Japan, 15 Sep. 2022, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal - Heavy Fermion Emerging from the Singular Fermi Liquid in Underscreened Kondo Model for Eu Compounds
Shingo Kuniyoshi; Ryousuke Shiina
Journal of the Physical Society of Japan, 90, 12, Physical Society of Japan, 15 Dec. 2021, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal - Effect of Magnetic Field on Quantum Phase Transition and Heavy Fermion State in a Two-Orbital Impurity Anderson Model
Ryousuke Shiina; Shingo Kuniyoshi
Journal of the Physical Society of Japan, 90, 7, 074708, 074708, Physical Society of Japan, 15 Jul. 2021, [Peer-reviewed], [International Magazine]
English, Scientific journal - Valence Fluctuation, Spin–Orbit Coupling, and Magnetic–Nonmagnetic Crossover in Eu Compounds
Shingo Kuniyoshi; Ryousuke Shiina
Journal of the Physical Society of Japan, 89, 12, 124711, 124711, Physical Society of Japan, 15 Dec. 2020, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal - Fermionic order by disorder in a van der Waals antiferromagnet
R. Okuma; D. Ueta; S. Kuniyoshi; Y. Fujisawa; B. Smith; C. H. Hsu; Y. Inagaki; W. Si; T. Kawae; H. Lin; F. C. Chuang; T. Masuda; R. Kobayashi; Y. Okada
Scientific Reports, 13, 1, Springer Science and Business Media {LLC}, 17 Sep. 2020, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal,
CeTe
is a unique platform to investigate the itinerant magnetism in a van der Waals (vdW) coupled metal. Despite chemical pressure being a promising route to boost quantum fluctuation in this system, a systematic study on the chemical pressure effect on Ce
(4
) states is absent. Here, we report on the successful growth of a series of Se doped single crystals of CeTe
. We found a fluctuation driven exotic magnetic rotation from the usual easy-axis ordering to an unusual hard-axis ordering. Unlike in localized magnetic systems, near-critical magnetism can increase itinerancy hand-in-hand with enhancing fluctuation of magnetism. Thus, seemingly unstable hard-axis ordering emerges through kinetic energy gain, with the self-consistent observation of enhanced magnetic fluctuation (disorder). As far as we recognize, this order-by-disorder process in fermionic system is observed for the first time within vdW materials. Our finding opens a unique experimental platform for direct visualization of the rich quasiparticle Fermi surface deformation associated with the Fermionic order-by-disorder process. Also, the search for emergent exotic phases by further tuning of quantum fluctuation is suggested as a promising future challenge.
- 多体系におけるアトミックな拡張多極子の分類
國吉真伍; 大岩陸人; 速水賢
日本物理学会, 26 Mar. 2026, Oral presentation - A Classification of Atomic Many-Body Operators Based on Augmented Multipoles
Shingo Kuniyoshi; Rikuto Oiwa; Satoru Hayami
2nd Japan-Germany Workshop Correlated and Topological Quantum Materials, 03 Mar. 2026, Poster presentation - アトミックな多体演算子の多極子的分類とトロイダル・キラルスカラー
國吉真伍; 大岩陸人; 速水賢
アシンメトリ量子令和7年度領域全体会議・成果報告会, 07 Jan. 2026, Poster presentation - 局所多体系の多極子的分類とキラルスカラー
國吉真伍; 大岩陸人; 速水賢
物性科学領域領域横断研究会, 27 Dec. 2025, Poster presentation - キラル結晶XSi2（X=V, Nb, Ta）の拡張多極子による解析
國吉真伍; 楠瀬博明; 大岩陸人
琉球物性研究会, 23 Nov. 2024, Oral presentation - Eu系アンダースクリーニング近藤効果における価数揺らぎの影響
國吉真伍; 椎名亮輔
琉球物性研究会, 25 Nov. 2023, Oral presentation - Eu系異方的アンダースクリーン近藤モデルにおける磁場効果
國吉真伍; 椎名亮輔
日本物理学会, 18 Sep. 2023, Oral presentation - Mechanism of Novel Heavy Fermion Formation in the Weakly Anisotropic Ferromagnetic Kondo Model
Shingo Kuniyoshi; Ryousuke Shiina
International Conference on Strongly Correlated Electron Systems, 03 Jul. 2023, Poster presentation - 強磁性的不純物近藤モデルにおける階層的近藤一重項
國吉真伍; 椎名亮輔
日本物理学会, 24 Mar. 2023, Poster presentation - アンダースクリーン近藤状態における結晶場効果と磁場効果
國吉真伍; 椎名亮輔
琉球物性研究会, 17 Dec. 2022, Oral presentation - Kondo effect and valence fluctuation in Eu-based impurity Anderson model
Shingo Kuniyoshi; Ryousuke Shiina
29th International Conference on Low Temperature Physics, 23 Aug. 2022, Poster presentation - Emergence of heavy local Fermi liquid in the underscreened Kondo model with easy-plane anisotropy
Shingo Kuniyoshi; Ryousuke Shiina
International Conference on Strongly Correlated Electron Systems, 25 Jul. 2022, Poster presentation - アンダースクリーン近藤状態から発現する重い電子
國吉真伍; 椎名亮輔
日本物理学会, 16 Mar. 2022, Oral presentation - Eu系における結晶場誘起型重い電子
國吉真伍; 椎名亮輔
琉球物性研究会, 18 Dec. 2021, Oral presentation - Eu系2軌道アンダーソンモデルにおける価数揺らぎと近藤効果
國吉真伍; 椎名亮輔
日本物理学会, 20 Sep. 2021, Poster presentation - Eu系不純物アンダーソン模型における多軌道c-f混成による価数揺らぎの解析
國吉真伍; 椎名亮輔
日本物理学会, Mar. 2021, Poster presentation - Eu化合物における価数揺動，スピン軌道相互作用，磁性 - 非磁性クロスオーバー
國吉真伍; 椎名亮輔
琉球物性研究会, 19 Dec. 2020, Oral presentation - Eu化合物における価数揺動，スピン軌道相互作用，磁性 - 非磁性クロスオーバー
國吉真伍; 椎名亮輔
日本物理学会, 10 Sep. 2020, Oral presentation - Numerical renormalization group study of an impurity Anderson model for the Eu compounds
S. Kuniyoshi; R. Shiina
The 3rd Univ. Ryukyus International Symposium of Theoretical and Computational Science 2020, 20 Mar. 2020, Oral presentation - Eu系不純物アンダーソン模型の数値くり込み群による解析
國吉真伍; 椎名亮輔
日本物理学会, 17 Mar. 2020, Poster presentation - 層状希土類カルコゲナイド化合物の単結晶作成と物性研究
國吉 真伍; 藤澤 唯太; 小林 理気; 岡田 佳憲
日本物理学会, 11 Sep. 2018, Poster presentation
■ Academic and Social Contribution Activities/Other
Others
