計算物理学ー物性研究における新展開ーAO2相関の強い量子系

1992 Fiscal Year Annual Research Report

• Project/Area Number: 04231105
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: 斯波 弘行 東京工業大学, 理学部, 教授 (30028196)
• Co-Investigator(Kenkyū-buntansha): 坂井 徹 姫路工業大学, 理学部, 助手 (60235116) ; 倉本 義夫 東北大学, 理学部, 教授 (70111250) ; 酒井 治 東北大学, 理学部, 助教授 (60005957) ; 永長 直人 東京大学, 工学部, 助教授 (60164406) ; 安藤 恒也 東京大学, 物性研究所, 教授 (90011725)
• Keywords: 量子モンテカルロ法 / 強相関電子系 / 一次元量子系 / スーパーコンピューター / 二次元電子系

Research Abstract

本研究班は、解析的方法のみでは解決因難な「量子効果の顕著な相関の強い系」をスーパーコンピューターやワークステーションを活用して数値的方法により解決すること、その為の新しい方法やアルゴリズムの開発を目的としている。本年度の成果としては以下のものがある。
磁場中の二次元電子の示す量子ホール効果についてedge stateの重要性が示され(安藤)、二次元と一次元の中間的系の分数量子ホール効果の興味ある性質が明らかにされた。(吉岡)
数値繰り込み群の方法の発展に関しては、(1)超伝導体中の近藤効果についての詳細な研究(斯波、酒井)(2)半導体中の磁性不純物(酒井)(3)内部構造が重要な希土類の近蒔効果(酒井)、などが研究された。
量子モンテカルロ法の発展としては、二次元ハバード模型と一次元系の比較により、両者の類似点、相違点が明らかにされ(今田)、また、半導体中の磁性不純物について量子モンテカルロ法と数値繰り込み群の結果がよく一致することが示された。(佐素)
高温超伝導に関係した成果としては、二次元Abrikosor格子の融解のモンテカルロシミュレーション(永長)が新しい成果である。
新しい厳密解をもつモデルの発見とそれをコンピュターを用いて「証明」という、コンピューターの新しい利用法により一次元のt-Jモデルを一般化したモデルの存在が報告され、注目をあびた。(倉本)
昨年度からの継続として、Haldaneギャップ問題について異方性などを取り入れて「相図」を作成する仕事がなされた。(坂井、高橋)
以上簡単に述べた研究は昨年開かれたいくつかの国際会議で報告され国際的評価をえている

Research Products

• [Publications] Th.Pruschke and H.Shiba: "Superconducting Correlations in One-Dimensional t-J Model" Phys.Rev.B. 46. 356-365 (1992)
• [Publications] K.Satori,H.Shiba,O.Sakai and Y.Shimizu: "Numerical Renormalization Group Study of Magnetic Impurities in Superconductors" J.Phys.Soc.Jpn.61. 3239-3254 (1992)
• [Publications] T.Ohyama and H.Shiba: "Effective Hamiltonian and Phase Transitions of Hexagonal Heisenberg Antiferromagnets with Easy-Axis Anisotropy" J.Phys.Soc.Jpn.61. 4174-4186 (1992)
• [Publications] H.Shiba and M.Ogata: "Properties of One-Dimensional Strongly Correlated Electrons" Prog.Theor.Phys.Suppl.108. 265-286 (1992)
• [Publications] O.Sakai,Y.Shimizu,T.Kasuya: "Excitation Spectra of the Impurity Anderson Model Calculated by the Numerical Renormalization Group Method" Progress of Theoretical Physics,Supplement. 108. 73-88 (1992)
• [Publications] O.Sakai,Y.Shimizu: "Excitation Spectra of the Two Impurity Anderson Model.I" Journal of The Physical Society of Japan. 61. 2333-2347 (1992)
• [Publications] O.Sakai,Y.Shimizu: "Excitation Spectra of the Two Impurity Anderson Model.II" Journal of The Physical Society of Japan. 61. 2348-2358 (1992)
• [Publications] K.Satori,H.Shiba,O.Sakai,Y.Shimizu: "Numerical Renormalization Group Study of Magnetic Impurities in Superconductors" Journal of The Physical Society of Japan. 61. 3239-3254 (1992)
• [Publications] K.Takegahara,Y.Shimizu,O.Sakai: "Quantum Monte Carlo and Numerical Renormalization Group Studies of Magnetic Impurities in Nonmetallic Systems" Journal of The Physical Society of Japan. 61. 3443-3446 (1992)
• [Publications] M.Takeshige,R.Takayama,O.Sakai,T.Kasuya: "Dynamical Screening by d-Electron in Optical and Virtual Excitation in f-Electron Systems" Japanese Journal of Applied Physics Series Physical Properties of Actinide and Rare Earth Compounds. 8. 129-138 (1993)
• [Publications] T.Saso: "Variational and Self-Consistent Perturbational Theories for Generalized Kondo Problems" Prog.Theor.Phys.Suppl.108. 89-116 (1992)
• [Publications] T.Saso: "1/N and Quantum Monte Carlo Studies of a Magnetic Impurities in an Insulator with a small Gap" J.Phys.Soc.Jpn.61. 3439-3442 (1992)
• [Publications] T.Saso and J.Ogura: "Kondo Insulator-1/N and Quantum Monte Carlo Studies" Physica B. (1993)
• [Publications] Y.Kuramoto: "Exact dynamics of highly correlated electron in two dimensions" New Horizons in Low-Dimensional Electron Systems (H.Aoki,M.Tsukada,M.Schluter and F.Levyeds.,Klawer Academic Publishers,The Netherlands). 247-260 (1992)
• [Publications] 本田 泰,倉本 義夫,渡辺 剛: "厳密対角化法による銅酸化物のスピン状態" 豊田研究報告. 45. 47-52 (1992)
• [Publications] H.Yokoyama and Y.Kuramoto: "Generalized Gutzwiller states as exact excited states in the one-dimensional supersymmetric t-J model with long-range exchange and transfer" J.Phys.Soc.Jpn. 61. 3046-3049 (1992)
• [Publications] 倉本 義夫: "長距離相互作用のある超対称t-Jモデルの厳密解" 固体物理. 28. 40-47 (1993)
• [Publications] Y.Kuramoto: "Supersymmetric long-range t-J model as a new canomical model for strongly conelated formions" Physica B. (1993)
• [Publications] Y.Honda,Y.Kuramoto and T.Watanabe: "Effects of cyclic 4-spin exchange on magnetic properties of the Cu3_2 plane" Phys.Rev.B. (1993)
• [Publications] Kenn Kubo: "Spin correlations in the S=1 XXZ chain" Physical Review B. 46. 866-873 (1992)
• [Publications] Kenn Kubo and Masahito Tada: "Errata:The High Temperature Series for the Single -Band Habbard Model in the Strong Correlation Limit,I and II" Progress of Theoretical Physics. 88. 155-155 (1992)
• [Publications] T.Ando: "Edge and Bulk Landau States in Quantum Hall Regime" J.Phys.Soc.Jpn.61. 415-418 (1992)
• [Publications] S.Wakahara and T.Ando: "Theory of Hot-Electron Transport in Strong Magnetic Fields" J.Phys.Soc.Jpn.61. 1257-1270 (1992)
• [Publications] T.Ando and H.Tamura: "Conductance Fluctuations in Quantum Wires with Spin-Orbit and Boundary Roughness Scattering" Phys.Rev.B. 46. 2332-2338 (1992)
• [Publications] Y.Nakazawa: "Low-temperature magnetic properties of the ferromagnetic organic radical,p-nitrophenyl nitronyl nitroxide" Phys.Rev.B. 46. 8906-8914 (1992)
• [Publications] M.Takahashi: "Mean-field theory of quasi one-dimensional Heisenberg magnet γ-phase p-NPNN" J.Phys.Soc.Jpan. 61. 3745-3751 (1992)
• [Publications] M.Takahashi: "Dynamics and Statics of La_2CuO_4" The Physics and Chemistry of Oxide Superconductors (Springer). 429-431 (1992)
• [Publications] M.Takahashi: "2D antiferromagnets by modified spin-wave theory" J.Magn.Magn.Mat.104-107. 845-846 (1992)
• [Publications] M.Takahasi: "Numerical calculation of S=1 Heisenberg antiferromagnetic chain" Computational approaches in Condensed Matter Physics (Springer). 152-156 (1992)
• [Publications] T.Sakai: "Haldane antiferromagnet in a magnetic field" Computational approaches in Condensed Matter Physics (Springer). 171-172 (1992)
• [Publications] Masatoshi Imada: "On Dimer Pairing Mechanism of Superconductivity" Journal of The Physical Society of Japan. Vol.61. 423-427 (1992)
• [Publications] Nobuo Furukawa and Masatoshi Imada: "Two-Dimensional Hubbard Model--Metal Insulator Transition Studied by Monte Carlo Calculation--" Journal of The Physical Society of Japan. Vol.61. 3331-3354 (1992)
• [Publications] Masatoshi Imada,Nobuo Furukawa and T.M.Rice: "Crossover of Spin Correlations in the One-Dimensional Hubbard Model" Journal of The Physical Society of Japan. Vol.61. 3861-3864 (1992)
• [Publications] Naoto Nagaosa and Patrick A.Lee: "Quantum disordered spiral states" Phys.Rev.B. 45. 10719-10727 (1992)
• [Publications] Ptrick A.Lee and Naoto Nagaosa: "Gauge theory of the normal state of high-Tc superconductors" Phys.Rev.B. 46. 5621-5639 (1992)
• [Publications] Yusuke Kato and Naoto Nagaosa: "First-Order Melting Transition of 2D Flux Line Lattice" Phys.Rev.B. 47. (1993)
• [Publications] Naoto Nagaosa: "RVB VS Fermi Liquid Picture of High-Tc Superconductors" J.Phys.Chem.Solids. 53. 1493-1498 (1992)
• [Publications] Naoto Nagaosa: "Some new aspects of RVB theory in high-Tc cuprates" Physica B. (1993)
• [Publications] Akira Furusaki and Naoto Nagaosa: "Resonant Tunneling in a Luttinger Liquid" Phys.Rev.B. 47. (1993)
• [Publications] Daijiro Yoshioka: "Fractional Quantum Hall states in Narrow Channels" Journal of the Physical Society of Japan. 62. 839-842 (1993)
• [Publications] Daijiro Yoshioka: "Fractional Quantum Hall Effect in Narrow Channels" Physica B. (1992)
• [Publications] T.Sakai and M.Takahashi: "Anisotropic S=1 Antiferromagnetic Heisenberg Chain in a Magnetic Field" J.Phys.Soc.Jpn.62. (1993)
• [Publications] T.Sakai: "S=1 Antiferromagnetic Heisenberg Chain in a Magnetic Field" Proceedings of 2nd International Conference on Computer Applications to Materials and Molecular Science and Engineering. (1993)
• [Publications] T.Sakai and M.Takahashi: "Finite-Size Correction and Spin Correlations of Magnetized S=1 Antiferromagnetic Heisenberg Chain" J Phys.Soc.Jpn.60. 3615-3619 (1991)
• [Publications] T.Sakai and M.Takahashi: "S=1 Antiferromagnetic Heisenberg Chain with an Axial-Symmetry-Breaking Anisotropy" Phys.Rev.B. B44. 10385-10388 (1991)
• [Publications] T.Sakai and M.Takahashi: "S=1 Antiferromagnetic Heisenberg Chain in a Magnetic Field" Phys.Rev.B. B43. 13383-13393 (1991)
• [Publications] M.Takahasi and T.Sakai: "Magnetization Curve and Correlation Function of Haldune-Gap Antiferromagnet in Strong Magnetic Field" J.Phys.Soc.Jpn.60. 760-763 (1991)
• [Publications] M.Kikuchi and Y.Okabe: "Order-Perameter Distribution Function and Order of the Phase Transition of the Ferocmagnetic Potts Model" J.Phys.Soc.Jpn.61. 3503-3510 (1992)
• [Publications] K.Satoh and Y.Okabe: "Critical Phenomenon in a Neural Network Model:A Localization-Delocalization Transition of Excited Clusters" J.Phys.Soc.Jpn.62. 64-71 (1993)
• [Publications] H.Otsuka: "Variational Monte Carlo Studies of the Hubbard Model in One-and Two-Dimensions-off Diagonal Intersite Correlation Effects-" J.Phys.Soc.Jpn.61. 1645-1656 (1992)