Dynamics of Disordered Non-Equilibrium Systems: Hysteresis, Noise, and Domain Wall Dynamics in Systems Ranging from Magnets to Earthquakes

许多系统“爆裂”；当缓慢推进时，它们会以大小和持续时间的广泛分布的离散事件做出响应。地球对缓慢的构造运动做出反应，地震的大小从微小的震动到毁灭性的九次地震不等。同样，磁带在缓慢变化的外部磁场中以一系列跳跃(巴克豪森噪声)磁化-从微观到宏观大小的重定向磁域的雪崩。在过去的几年里，在驱动的、无序的、非线性的、动态的系统中，在发展标度不变的、通常是普遍的行为的模型和理论方面取得了快速的进展。这个理论项目将仔细地对照实验结果测试其中一些模型，为未来的实验提取普遍的预测，如果必要的话，扩展模型以充分描述实验，并探索相应的普适性类的大小。所采用的方法范围从数值模拟到标度理论，并借鉴了从流体力学到动力学和无序系统理论的各种思想。智力优势：巴克豪森噪声是研究滞后系统中集体“爆裂”噪声的理想实验样例系统。对于非破坏性测试，它相对容易进行实验，并且也具有商业价值。非平衡零温度随机场伊辛模型(RFIM)和最新的变种(其应用远远超出磁系统)在模拟一大类不同材料的巴克豪森噪声测量获得的普适标度指数方面取得了非凡的成功。在有限场扫描速率下将温度涨落添加到模型中，将探索从远平衡到近平衡的整个实验相关的交叉区域，并与最近在磁性和铁电系统中的实验进行比较。我们将详细比较相应的平衡普适性和非平衡普适性，以回答与实验和应用相关的长期存在的问题。参与该项目的学生将获得广泛的技能，并学习如何与理论家、实验者以及可能的行业代表合作。这项研究的结果除了具有非常重要的基础意义外，还具有技术应用的前景。%许多系统“破裂”；当缓慢推进时，它们会以大小和持续时间的广泛分布的离散事件做出响应。地球对缓慢的构造运动做出反应，地震的大小从微小的震动到毁灭性的九次地震不等。同样，磁带在缓慢变化的外部磁场中以一系列跳跃(巴克豪森噪声)磁化-从微观到宏观大小的重定向磁域的雪崩。在过去的几年里，在驱动的、无序的、非线性的、动态的系统中，在发展标度不变的、通常是普遍的行为的模型和理论方面取得了快速的进展。这个理论项目将仔细地对照实验结果测试其中一些模型，为未来的实验提取普遍的预测，如果必要的话，扩展模型以充分描述实验，并探索相应的普适性类的大小。所采用的方法范围从数值模拟到标度理论，并借鉴了从流体力学到动力学和无序系统理论的各种想法。

Many systems "crackle"; when pushed slowly they respond with discrete events in a broad distribution of sizes and durations. The earth responds to slow tectonic motion with quakes ranging in size from tiny tremors to devastating multitude-nine quakes. Similarly, a magnetic tape in a slowly changing external magnetic field magnetizes in a series of jumps (Barkhausen noise) - avalanches of reorienting magnetic domains that range from microscopic to macroscopic in size.In the past few years there has been rapid progress in developing models and theories of scale-invariant, often-universal behavior in driven, disordered, nonlinear, dynamical systems. This theoretical project will carefully test some of these models against experimental results, extract universal predictions for future experiments, extend the models if necessary to adequately describe experiments, and explore the size of the corresponding universality classes. The methods employed range from numerical simulations to scaling theories, and draw on ideas ranging from hydrodynamics to dynamical and disordered systems theory.Intellectual merit: Barkhausen noise serves as an ideal experimental example system for studying collective "crackling" noise in hysteretic systems. It is relatively accessible to experiments and is also of commercial interest, as for non-destructive testing. The non-equilibrium zero temperature random field Ising model (RFIM) and recent variants (with applications far beyond magnetic systems) have been extraordinarily successful in modeling universal scaling exponents obtained from Barkhausen noise measurements in a large class of different materials. Adding temperature fluctuations to the model at finite field sweep rate, the entire experimentally relevant crossover regime from far-from equilibrium to close-to equilibrium will be explored and compared to recent experiments in magnetic and ferroelectric systems. The corresponding equilibrium and non-equilibrium universality classes will be compared in detail, to answer long-standing questions relevant to both experiments and applications.Broader impact is two-fold. Students involved with the project will gain a broad range of skills and learn to work with groups of theorists, experimentalists and possibly industrial representatives. Besides being of great fundamental importance, the results of this research hold promise of technological applications.%%%Many systems "crackle"; when pushed slowly they respond with discrete events in a broad distribution of sizes and durations. The earth responds to slow tectonic motion with quakes ranging in size from tiny tremors to devastating multitude-nine quakes. Similarly, a magnetic tape in a slowly changing external magnetic field magnetizes in a series of jumps (Barkhausen noise) - avalanches of reorienting magnetic domains that range from microscopic to macroscopic in size.In the past few years there has been rapid progress in developing models and theories of scale-invariant, often-universal behavior in driven, disordered, nonlinear, dynamical systems. This theoretical project will carefully test some of these models against experimental results, extract universal predictions for future experiments, extend the models if necessary to adequately describe experiments, and explore the size of the corresponding universality classes. The methods employed range from numerical simulations to scaling theories, and draw on ideas ranging from hydrodynamics to dynamical and disordered systems theory.***