Dynamics of Extended Non-Equilibrium Systems: Hysteresis, Electromigration, and Defect Chaos

9419506在长时间尺度上出现的塞纳纳集体行为将在三个系统中进行探索。首先，研究人员将研究与某些磁滞回线相关的无序诱导的爆发成核，并研究其在磁记录方面的创新应用。其次，我们将对大型移动空洞的动力学进行解析研究，并使用大量铝和铜的真实模拟。这项工作将有助于理解高电流密度微细加工器件中存在的失效现象。第三，研究由偏微分方程描述的二维系统中的混沌状态，这些系统的拓扑缺陷以混沌、湍流的方式运动。更一般的粗粒化方法将被用来研究相变和边界的影响，并了解这些系统中噪声的性质。对于许多系统来说，尽管单个粒子相互作用的基本物理是复杂的，但在大范围内往往可以找到相当简单的定律。我们将从理论上研究这类系统被迫远离平衡的三个例子。首先，某些系统，如磁铁，根据参数(如外部磁场)的增大或减小而表现出不同的行为。将对这种系统进行研究，并将这些结果应用于磁记录。其次，将使用方程和计算机模拟来研究铝和铜等材料中空穴(气囊)的运动，目的是更好地了解流经它们的高电流微制造器件中的故障。第三，将在某些类别的二维系统中研究混沌噪音和缺陷的行为，例如被迫流动的液体和心肌壁。***

9419506 Sethna Collective behavior emerging on long length scales will be explored in three systems. First, the investigator will study disorder-induced nucleation of bursts associated with certain hysteresis loops and investigate innovative applications to magnetic recording which result. Second, the dynamics of large, mobile voids will be studied analytically and using realistic simulations of bulk aluminum and copper. This work will help understand failure present in microfabricated devices with high current densities. Third, chaotic states in two-dimensional systems described by partial differential equations whose topological defects move in a chaotic, turbulent manner will be studied. More general coarse-graining methods will be used to investigate phase transitions and the effects of boundaries, and to understand the nature of noise in these systems. %%% For many systems, even though the underlying physics of the interactions of the individual particles is complex, on a large scale rather simple laws can often be found. Three examples of such systems that are forced to be far from equilibrium will be investigated theoretically. First, certain systems, such as magnets, behave differently depending on whether a parameter (such as an external magnetic field) is increased or decreased. Such systems will be investigated and these results will be applied to magnetic recording. Second, the movement of voids (pockets of air) in materials such as aluminum and copper will be investigated using equations and computer simulations, with a goal to better understand failure in microfabricated devices with high currents flowing through them. Third, the behavior of chaotic noise and defects will be investigated in certain classes of two-dimensional systems, such as fluids that are forced to flow and heart muscle walls. ***