Hierarchy, Dynamics and Memory Phenomena of Metastable States in Random Systems

随机系统亚稳态的层次结构、动力学和记忆现象

• 批准号: 62540262
• 负责人: HAJIME TAKAYAMA
• 金额: $ 1.22万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62540262/
• 关键词: Mean-Field Theory of Spin Glasses; Ultrametricity of Metastable States; Re-entrant Transition; Naive Mean-Field Model; Nonlinear Dynamical System with Randomness; Mode-Locking Phenomena; Noises in CDW Current; CDW電流の確率的な振舞い; 自由エネルギーの多谷構造; ナイーブ平均場

In a random system with frustrations in its interactions there exist a number of metastable states, and its free energy seen in a certain phase space has complicated multi-valley structure. In this project we aimed to get deeper understandings on hierarchical structure of such metastable states, and on dynamics and memory phenomena associated with them. For this purpose we have analyzed in detail a few mean-field models for spin glasses. A charge-density-wave (CDW) system in quasi one-dimensional conductors exhibits a variety of electric conduction phenomena. We have also tried to understand them in a unified way from the view-point that the CDW is a nonlinear dynamical system with spin-glass-like randomness. The analyses here are based on the Fukuyama-Lee-Rice (FLR) model, in which the CDW is regarded as a continuum obeying classical mechanics. The following points are clarified in this project.1. Mean-Field Models of Spin Glasses:(1) The free energy structure of the SK model is in fa … More ct ultrametric, and the relaxation of a state by thermally activated processes obeys the stretched exponential law. (2) A proper extension of the sk model in such a way as to extract characteristic features of the interactions in each material is able to explain spin-glass phenomena, such as the re-entrant transition, of the material in certain detail. (3) The spin-glass picture derived on the SK model holds true also on the 'naive' mean-field model, in which Onsager's reaction field in the SK model is discarded.2. CDW Dynamics:(1) The nonlinear conductivity of the FLR model exhibits characteristic dependence on the dimensionality of the system. Its 3d behavior is compatible with experimental results. (2)Mode-locking phenomena in the CDW system can be interpreted as cooperative ones induced by the external ac field. (3) When the heat-bath effect is included, the stochastic behavior of the CDW current in the FLR model corresponds qualitatively to the recently observed results on the width of the narrow-band-noise peak and on the 1/f-type broad-band-noise. These phenomena are considered to originate from the stochastic transition of the system between many sliding configurations of the CDW which are close to a stationary one. Less

在其相互作用中有挫败感的随机系统中，存在许多亚稳态，并且在特定相空间中看到的自由能具有复杂的多谷结构。在这个项目中，我们旨在对这种亚稳态状态的层次结构以及与之相关的动态和记忆现象进行更深入的理解。为此，我们详细分析了一些自旋玻璃的平均场模型。准一维导体中的电荷密度波（CDW）系统表现出各种电导传导现象。我们还试图以统一的方式理解它们，从CDW是具有旋转玻璃的随机性的非线性动态系统。这里的分析基于福山 - 李 - 利斯（FLR）模型，其中CDW被视为持续遵守的经典力学。在本项目中阐明了以下几点。1。自旋玻璃的平均场模型：（1）SK模型的自由能结构在FA中……更多的CT超级量，并且通过热激活过程对状态的放松遵守拉伸指数定律。 （2）SK模型的适当扩展方式以提取每种材料中相互作用的特征特征能够解释材料的旋转玻璃现象，例如重新输入过渡，以某些详细的方式解释。 （3）在SK模型上得出的旋转玻璃图片在“幼稚”平均场模型上也是正确的，其中SK模型中的Onsager反应场被丢弃2。 CDW动力学：（1）FLR模型的非线性电导率表现出对系统维度的特征依赖性。它的3D行为与实验结果兼容。 （2）CDW系统中的模式锁定现象可以解释为外部AC场引起的合作。 （3）当包括热浴效果时，FLR模型中当前CDW的随机行为对应于最近观察到的窄带 - 噪声峰宽度以及1/F型宽频段噪声的结果。这些现象被认为是源于系统在CDW的许多滑动构型之间的随机跃迁，而CDW接近固定的构型。较少的

项目成果

Masakatsu ISHIKAWA.: Prog.Theor.Phys.79. 359-372 (1988)

石川正胜：Prog.Theor.Phys.79。

Hiroshi MATSUKAWA.: J.Phys.Soc.Jpn.57. 3463-3473 (1988)

松川浩：J.Phys.Soc.Jpn.57。

Masakatsu ISHIKAWA: "On the Phase Dynamics of One-Dimensional Incommensurate Charge-Density-Wave in an Electric Field" Prog. Theor. Phys.79. 359-372 (1988)

Masakatsu ISHIKAWA：“电场中一维不相称电荷密度波的相位动力学”Prog。

Hiroshi MATSUKAWA: Proc. 18th Int. Conf. on Low Temp. Phys., Kyoto, 1987 Jpn. J. Appl. Phys.26 Suppl.601-602 (1987)

松川浩：Proc。

Hiroshi MATSUKAWA: J.Phys.Soc.Jpn.57. 3463-3473 (1988)

松川浩：J.Phys.Soc.Jpn.57。