Statistical Physics of Fluctuations in Glassy

在这个项目中，通过法国、美国和日本的研究人员以及实验学家和理论家的密切合作，研究了支配自旋玻璃等玻璃体系中平衡和非平衡动力学的涨落的基本性质。各个小组（或个别成员）对系统中的各个主题进行了单独研究，并在1998年10月在法国Royaumont和1999年10月在京都举行的研讨会上讨论了他们的结果，所有成员都参加了研讨会，以寻找关于玻璃态系统中波动的共同概念。主要结果如下：1）关于自旋玻璃的老化现象：a）通过对自旋玻璃热释磁磁化强度的详细测量，提取了自旋玻璃（SG）关联长度，并从实验上建立了SG关联长度在老化过程中的增长规律（Orbach）。B.）在温度变化和循环协议中，自旋玻璃表现出 ...更多信息 显然是矛盾的现象，“返老还童”和“记忆效应”。一个理论框架，这是从相空间的观点，可以解释的现象一致，已被提出（Bouchaud），和现象进行了数值分析的基础上的“分层随机能量模型”，这是在这个框架内（根本）。c）另一方面，我们发现EA模型中对老化现象的模拟结果与描述真实的自旋空间中的现象的液滴图的预测吻合得很好。2）通过对无序铁磁体或铁电体中的老化现象与自旋玻璃中的老化现象的比较，已经提出，在前一种材料中的老化动力学被很好地解释为具有随机电势的介质中的畴壁的扩散运动（Bouchaud，Cugliandolo）。在玻璃态系统中的相变和涨落性质方面获得了下列新结果：把SG平均场理论推广到信息的统计计算（Nishimori），矢量自旋玻璃和高温陶瓷超导体中手性玻璃转变的理论（Kawamura），磁性和磁性陶瓷中的一种新型相变（Matsuura），自旋玻璃和聚合物玻璃共同的临界波动中的拉伸指数定律（坎贝尔），波动测量清楚地揭示了玻璃体系中的各种相变的不均匀性的作用（韦斯曼）。少

In this program, by the close collaboration of the researchers in France, US and Japan, as well as of the experimentalists and theorists, the fundamental nature of fluctuation which govern the equilibrium and non-equilibrium dynamics in glassy systems such as spin glasses has been studied. The various subjects in the systems have been individually investigated by the sub-groups (or individual members), and their results have been discussed in the workshops-at Royaumont, France, October 1998, and at Kyoto, October 1999-which all the members participated to look for a common concept(s) on fluctuations in the glassy systems. The main results obtained are as follows.1) Concerned with the aging phenomena in spin glasses : a) Through the detailed measurement of the thermoremanent magnetization, the spin-glass (SG) correlation length has been extracted and its growth law in aging has been experimentally established (Orbach). b.) In temperature-shift and cycling protocols spin glasses exhibit … More apparently paradoxical phenomena, the 'rejuvenation' and 'memory effect'. A theoretical framework, which is constructed in a viewpoint from the phase space and can explain the phenomena consistently, has been proposed (Bouchaud), and the phenomena are numerically analyzed based on the 'hierarchical random energy model' which is within this framework (Nemoto). c) On the other hand, it has been found that the simulational results on the aging phenomena in the EA model agree well with the predictions from the droplet picture which describes the phenomena in the real spin space.2) From, comparison of the aging phenomena in disordered ferromagnets or ferroelectrics with those in spin glasses, it has been proposed that the aging dynamics in the former materials is well interpreted as the diffusive motion of domain walls in a medium with random potentials (Bouchaud, Cugliandolo).3). The following new results have been obtained on phase transitions and nature of fluctuations in glassy systems : an extension of the SG mean-field theory to the statistical computations of information (Nishimori), theories on the chiral-glass transition in vector spin glasses and in high-Tc ceramic superconductors (Kawamura), a new type of phase transition in magnetic and superconductive ceramics (Matsuura), the stretched exponential law in the critical fluctuation common to spin glasses and polymer glasses (Campbell), and the fluctuation measurement which clearly reveals a role of the inhomogeneity on various phase transition in glassy systems (Weissman). Less