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1993 Fiscal Year Annual Research Report

計算物理学-物性研究における新展開-第III班コンプレックス系における協力現象

Research Project

Project/Area Number 04231102
Research InstitutionUniversity of Tsukuba

Principal Investigator

高山 一  筑波大学, 物理学系, 教授 (40091475)

Co-Investigator(Kenkyū-buntansha) 宮下 精二  京都大学, 人間環境学研究科, 助教授 (10143372)
西森 秀稔  東京工業大学, 理学部, 助教授 (70172715)
利根川 孝  神戸大学, 理学部, 教授 (80028167)
鈴木 増雄  東京大学, 理学部, 教授 (80013473)
池田 研介  京都大学, 基礎物理学研究所, 教授 (40151287)
Keywords数値的対角化法 / 量子モンテカルロ法 / 強制振動子法 / ハルデン磁性体 / ハイゼンベルグスピングラス / カイラル相転移 / 多自由度量子カオス系 / 大域結合カオス系
Research Abstract

今年度も各班員は昨年度に引き続いて、計算物理学の手法の開発・適用によって、種々の複雑な系が示す協力現象の研究を進め、多くの成果を得た。領域研究全期間の成果は来年度に詳しくまとめるので、以下には今年度の成果のうち、主立ったものを報告する。
1]量子スピン系:S=1の-次元反強磁性体(ハルデン磁性体)について、次近接相互作用と異方性エネルギーがある場合の基底状態の詳細や不純物の効果が数値的対角化法によって明らかにされ(利根川)、この磁性体の有限温度における熱力学的性質が量子モンテカルロ法によって詳しく解析された(宮下)。また、量子系全般の高精度計算のための指数関数演算子の高次分解法に関して、その基礎と応用が調べられた(鈴木)。
2]ランダムスピン系:RKKY相互作用型のハイゼンベルグスピングラス(HSG)系において、自発磁化に垂直なスピン成分がランダムに凍結する混合相(リエントラント相)が強磁性相の低温側に出現することを、シミュレーションによる研究としては初めて示した(松原)。また、三次元短距離相互作用型HSGについて、個々のスピンの緩和過程まで立ち入ったシミュレーションイによりその臨界緩和現象の詳細が明らかにされ(高山)、また、温度領域を低温側に広げたシミュレーションにより、同系においてカイラル相転移が存在する可能性がきわめて大きいことが示された(川村)。
3]その他の複雑系:拡張された強制振動子法により、フラクタル反強磁性体のマグノンスペクトルが単一の変数でスケールされることが検証された(中山)。また、多自由度量子カオス系に関して、自己組織された散逸現象、動的局在、カオティック・トンネリング等の新しい描像が提起、検証された(池田)。大域結合カオス系に関しても、その対流現象や生物学的ネットワークへの適用により、新たな描像が得られた(金子)。

  • Research Products

    (48 results)

All Other

All Publications (48 results)

  • [Publications] H.Takayama: "Slow Dynamics in 3D ±J Heisenberg Spin Glass Monte Carlo Analysis of Auto-Correlation Functions of Individual Spins" Physica A. (in press). (1993)

  • [Publications] K.Ikeda: "Self-organization of dissipation in classically chaotic quantum systems" Annals of Physics. 227. 1-75 (1993)

  • [Publications] H.Yamada: "Quantum diffusion in a coherently time-varying one-dimensional disordered system" Physics Letters A. 182. 77-80 (1993)

  • [Publications] A.Shudo: "Toward the classical understanding of quantum chaological phenomena:dynamical localization and chaotic tunneling" Progress of Theoretical Physics Supplement(to be published). (1994)

  • [Publications] T.Yanagita: "Coupled Map Lattice for Convection" Phys.Lett.A. 175. 415-420 (1993)

  • [Publications] T.Yamamoto: "He Atom as a Classical 3-body Problem" Phys.Rev.Lett. 70. 1928-1931 (1993)

  • [Publications] K.Kaneko: "Chaotic Traveling Wave in Coupled Map Lattices" Physica D. 68. 299-317 (1993)

  • [Publications] K.Tokita: "Remanent overlaps in the Hopfield model with zero temperature sequential dynamics" Prog.Theor.Phys.90. 329-335 (1993)

  • [Publications] K.Tokita: "The replica-symmetry-breaking solution and the“SK limit"of the Hopfield Model" J.Phys.A. 26. 6915-6925 (1993)

  • [Publications] K.Kaneko: "Relevance of Clustering to Biological Networks" Physica D. (in press). (1994)

  • [Publications] H.Kawamura: "Free Vortex Formation and Topological Phase Transitions of Two-Dimensional Spin Systems" Phys.Rev.B. 47. 1134-1137 (1993)

  • [Publications] H.Kawamura: "Simulation Studies on Chiral Order" Computer Aided Innovation of New Materials II. 395-401 (1993)

  • [Publications] H.Kawamura: "Phase Transitions in Triangular Spin Systems" Recent Advances in Magnetism of Transition Metal Compounds(ed.A.Kotani and N.Suzuki,World Scientific). 335-347 (1993)

  • [Publications] M.Kikuchi: "Statistical Dependence Time and Its Application to Dynamical Critical Exponent" J.Phys.Soc.Jpn.62. 3052-3061 (1993)

  • [Publications] M.Suzuki: "Improved Trotter-like Formula" Phys.Lett.A. 180. 232-234 (1993)

  • [Publications] M.Suzuki: "General Decomposition Theory of Ordered Exponentials" Proc.Japan Acad.69. 161-166 (1993)

  • [Publications] M.Suzuki: "Convergence of Unitary and Complex Decomposition of Exponential Operators" J.Math.Phys.34. 4892-4897 (1993)

  • [Publications] M.Katori: "On the CAM Canonicality of the Cluster-Variation Approximation" Prog.Theor.Phys.Supple.115(to be published). (1994)

  • [Publications] A.Lipowski: "Roughening Transition in the Blume-Emery-Griffiths Model" J.Phys.A. 26. 5695-5704 (1993)

  • [Publications] N.Hatano: "Correlation Length of the S=2 Antiferromagnetic Heisenberg Chain" J.Phys.Soc.Jpn.62. 1346-1353 (1993)

  • [Publications] Y.Nonomura: "Coherent Anomaly in Kosterlitz-Thouless-Type Transition in the S=1/2 XXZ Chain at the Ground State" J.Phys.Soc.Jpn.62. 3774-3777 (1993)

  • [Publications] N.Hatano: "Data Analysis for Quantum Monte Carlo Simulations with the Negative-Sign Problem" J.Phys.Soc.Jpn.(to be published). (1994)

  • [Publications] M.Kaburagi: "Impurity-Bond Effect of the Spin-1 Antiferromagnetic Heisenberg Chain" J.Phys.Soc.Jpn.62. 1848-1852 (1993)

  • [Publications] M.Kaburagi: "Effect of Spin-1/2 Impurity on Spin-1 Antiferromagnetic Heisenberg Chain" J.Phys.Soc.Jpn.63. 420-424 (1994)

  • [Publications] M.Kaburagi: "Energy versus Magnetic-Field Diagram of the Spin-1 Haldane System with an Impurity" Physica B. (to be published). (1994)

  • [Publications] T.Nakayama: "Vibrational problems of fractal networks" Fractals. 1. 806-817 (1993)

  • [Publications] K.Yakubo: "Spectral dimension of percolating Heisenberg antiferromagnets" J.Phys.Soc.Jpn.62. 2196-2199 (1993)

  • [Publications] T.Nakayama: "Strong localization of photons in aperiodic optical waveguides" Phys.Rev.B. 47. 9249-9253 (1993)

  • [Publications] T.Terao: "Dynamical structure factor and its scaling property of percolating Heisenberg antiferromagnets" Phys.Rev.B. 49(in press). (1994)

  • [Publications] T.Nakayama: "Dynamical properties of fractal networks;scaling,numerical simulations,and physical realizations" Rev.Mod.Phys.66(in press). (1994)

  • [Publications] H.Nishimori: "Retrieval dynamics of associative memory of the Hopfield type" J.Phys.A. 26. 859-871 (1993)

  • [Publications] Y.Ozeki: "Phase diagram of gauge glasses" J.Phys.A. 26. 3399-3429 (1993)

  • [Publications] T.Nakamura: "Quantum Monte Carlo simulation of the J1-J2 model" J.Phys.Soc.Jpn.62. 3062-3070 (1993)

  • [Publications] H.Nishimori: "Optimum decoding temperature for error-correcting codes" J.Phys.Soc.Jpn.62. 2973-2975 (1993)

  • [Publications] K.Fukamachi: "Specific heat of the quantum Hiesenberg antiferromagnet on the kagome lattice" Phys.Rev.B. 49. 651-654 (1994)

  • [Publications] M.Iguchi: "Hybrid Monte Carlo spin-dynamics simulation on metallic spin-glass alloys" Phys.Rev.B. 47. 2648-2654 (1993)

  • [Publications] T.Shirakura: "Phase Transition of Three-Dimensional Site-Random Ising Model with Short-Range Interactions" J.Phys.Soc.Jpn.62. 3007-3010 (1993)

  • [Publications] F.Matsubara: "Hybrid Monte-Carlo Spin-Dynamics Simulation of Short-Range ±J Heisenberg Models with and without Anisotropy" Prog.Theor.Phys.90. 471-498 (1993)

  • [Publications] F.Matsubara: "Reentrant Mixed Phase Transition in a Metallic Spin-Glass Alloy" J.Phys.Soc.Jpn.63. 416-419 (1993)

  • [Publications] T.Kawasaki: "Anomalous Size Dependence of Relaxation Time in the Fuzzy Spin Model" Prog.Theor.Phys.89. 985-993 (1993)

  • [Publications] S.Miyazawa: "A Modified Decoupling Cell Method of Quantum Monte Carlo Calculation" Prog.Theor.Phys.89. 1167-1173 (1993)

  • [Publications] S.Miyashita: "Effects of edges in S=1 Heisenberg antiferromagnetic chains" Phys.Rev.B. 48. 913-919 (1993)

  • [Publications] S.Miyashita: "Thermodynamic Properties of S=1 Antiferromagnetic Heisenberg Chains" J.Phys.Soc.Jpn.62. 1459-1462 (1993)

  • [Publications] H.Takano: "Ordering process in the kinetic Ising model on the honeycomb lattice" Phys.Rev.B. 48. 7221-7226 (1993)

  • [Publications] S.Yamamoto: "Thermodynamic properties of S=1 antiferromagnetic Heisenberg chains as Haldane systems" Phys.Rev.B. 48. 9528-9538 (1993)

  • [Publications] K.Kaneko: "Theory and Applications of Coupled Map Lattices" John Wiley and Sons, (1993)

  • [Publications] K.Kawasaki: "Formation,Dynamics and Statistics of Patterns" World Scientific, (1993)

  • [Publications] M.Suzuki: "Quantum Monte Carlo Methods in Condensed Matter Physics" World Scientific, (1993)

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Published: 1995-02-08   Modified: 2016-04-21  

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