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arXiv 1802.08845cond-mat.stat-mech
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老化自旋玻璃中的介观实空间结构:Edwards-Anderson模型

Mesoscopic real space structures in aging spin-glasses: the Edwards-Anderson model

Paolo Sibani, Stefan Boettcher

摘要:

在低于$T_{\rm c}$的几个温度下收集了3D Edwards-Anderson自旋玻璃的等温模拟数据,并与最近的致密胶体悬浮液模型进行了类比,解释为地震推翻的相邻自旋簇,与记录大小的能量波动相关的非平衡事件。我们数值表明,一个很好的近似,这些地震是统计独立的,并构成一个泊松过程,其平均增长的时间。翻转的团簇是模型的两个基态之一上的局部投影,并且随时间同样地几何地增长。在不同温度下收集的数据$T$可以通过用$T^{1.75}$缩放它们来崩溃,这是E-A模型迄今未被注意的特征,我们一方面与配置空间的几何形状有关,另一方面与实验记忆和复原效应有关。集群翻转的速率随集群的大小呈指数下降,最近假设在一个粗粒度模型的致密胶体动力学。实空间中团簇结构的演化最终与热回复磁化强度的衰减有关。我们的分析提供了一个非常规的粗粒度的描述自旋玻璃老化统计从属于泊松振动过程,并强调记录动力学作为一个可行的共同的理论框架,在不同的系统老化。

英文摘要:

Isothermal simulational data for the 3D Edwards-Anderson spin glass are collected at several temperatures below $T_{\rm c}$ and, in analogy with a recent model of dense colloidal suspensions,interpreted in terms of clusters of contiguous spins overturned by quakes, non-equilibrium events linked to record sized energy fluctuations. We show numerically that, to a good approximation, these quakes are statistically independent and constitute a Poisson process whose average grows logarithmically in time. The overturned clusters are local projections on one of the two ground states of the model, and grow likewise logarithmically in time. Data collected at different temperatures $T$ can be collapsed by scaling them with $T^{1.75}$, a hitherto unnoticed feature of the E-A model, which we relate on the one hand to the geometry of configuration space and on the other to experimental memory and rejuvenation effects. The rate at which a cluster flips is shown to decrease exponentially with the size of the cluster, as recently assumed in a coarse grained model of dense colloidal dynamics. The evolving structure of clusters in real space is finally sssociated to the decay of the thermo-remanent magnetization. Our analysis provides an unconventional coarse-grained description of spin glass aging as statistically subordinated to a Poisson quaking process and highlights record dynamics as a viable common theoretical framework for aging in different systems.

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