Noise Investigations of Condensed Matter Systems

大多数材料在不同的电、机械、磁和光学参数下表现出缓慢的波动，具有广泛的特征速率分布。尽管这种波动的频谱普遍存在一种简单的形式(1/f)，但正如过去的实验所证明的那样，涉及的机制多种多样。这些波动之所以令人感兴趣，主要有两个原因。首先，它们限制了各种传感器和设备的性能。其次，它们为研究材料的基本性质提供了有用的工具，特别是人们所知较少的玻璃材料类型，这种材料表现出部分冻结的随机结构。他们正在使用电、光和磁涨落技术来研究普通玻璃、玻璃金属、自旋玻璃、具有随机域结构的磁性材料以及其他系统。他们特别关注的是，随着温度的降低，冻结的随机结构如何从流动的随机结构中出现，以及在非常低的温度下，哪种类型的未冻结模式仍然存在。

Most materials exhibit slow fluctuations, with a broad distribution of characteristic rates, in a variety of electrical, mechanical, magnetic, and optical parameters. Despite the ubiquity of a simple form (1/f) for the frequency spectrum of such fluctuations, a wide variety of mechanisms are involved, as has been demonstrated in past experiments. These fluctuations are of interest for two general reasons. First, they limit the performance of a variety of sensors and devices. Second, they provide a useful tool to study fundamental properties of materials, especially the poorly understood types of materials known as glasses, which exhibit partially frozen random structures. They are using electrical, optical and magnetic fluctuation techniques to investigate ordinary glasses, glassy metals, spin glasses, magnetic materials with random domain structures, and other systems. Their particular focus is on how frozen random structures emerge from fluid random structures as temperature is lowered, and on what type of unfrozen modes remain at very low temperatures.