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弗兰克·维尔切克是麻省理工学院物理学教授、量子色动力学的奠基人之一。因发现了量子色动力学的渐近自由现象，他在2004年获得了诺贝尔物理学奖。
物理学家常常需要从噪音中识别出有用的信号，但在另一些情况下，噪音本身就是信号——这些随机涨落背后，可能藏着重大科学突破。
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19世纪德国哲学家叔本华 (Arthur Schopenhauer) 在《论噪音》一文中写道：“最有才华的人对任何形式的干扰、打断和分心都深恶痛绝，尤其是噪音带来的折磨。”他说的噪音指的是那些用耳朵听到的噪声，尤其是“马鞭抽打的噼啪声，让人憎恶，可以让头脑麻痹。”
对科学家来说，噪音是一个更加广泛的概念，它指代任何具有随机性的涨落。与噪音相对的是信号。信号传递的是人们需要的信息，是有用的。如何从杂乱的背景噪音中分辨出有趣的信号，是实验科学和统计学的重要组成部分。
但有时，噪音本身就是信号。在1905年这个奇迹之年，爱因斯坦取得了3项重要发现，其中两个（分子运动论和光量子假说）都是从噪声中发现的。而最近，关于噪音的创造性工作再次推动了基础物理学的一系列突破性进展。
如果在显微镜下观察悬浮在液体中的花粉颗粒，我们会发现它们在做无规则运动。爱因斯坦认为，这种无规则运动是由花粉颗粒受到一个个流体分子的随机碰撞导致的。基于这个解释，他能够为分子的存在提出一个令人信服的依据，并且确定它们的质量。在研究黑体辐射时，爱因斯坦在马克斯 · 普朗克的研究基础上，进一步证明了辐射流中的颗粒性意味着光是一份一份的，即量子的。今天，我们称其为光子。
在日常生活中，我们通常认为电流是平滑的。事实上，电流是由一个个离散的电荷载流子——通常是电子——形成的，这导致电流具有不可消除的颗粒性，即散粒噪声。散粒噪声在电流信号很弱的时候尤其明显，它的强度可以用来测量电子的电荷。1995年，科学家们利用散粒噪声发现了某些物质态中的带电粒子只携带分数电荷，从而证明了罗伯特·劳克林 (Robert Laughlin) 的惊人预言，并且开辟了一个全新的“亚电子”领域。
今年4月，《科学》杂志的封面文章宣布，物理学家们探测到了任意子——一种玻色子和费米子之外的第三类亚电子粒子。多年来，理论物理学家一直期待着发现这类粒子。（“任意子”是我在1982提出的名字。）
发现任意子的核心测量涉及到一种更复杂的散粒噪声 ：它不仅涉及单个电流的涨落，还涉及到两个电流涨落之间的关联。这项新的研究带来了众多全新的可能性，包括建造更高效的量子计算机。
关于电流的涨落以及它们之间的关联看上去似乎很深奥，但它们其实是我们思维模式的一个隐秘却至关重要的组成部分。我们大脑中的信息大部分是通过神经元的放电模式来编码的，而神经元的放电模式本质上就是电流脉冲。对于流经不同神经元的电流，它们涨落间的相互关联，承载了我们的感知与思维。
确实，噪音让人非常难受。我们受伤或发炎的时候会感到疼痛，这往往与受损神经的紊乱刺激有关。而癫痫更是一种神经上的噪音风暴。正如叔本华所写的 ：“一位具有伟大才华的智者，当其被打断、扰乱、分心或转移注意力时，也就与常人无异了。”但是如果噪音被分析和利用，它也可以成为一种宝贵的资源。
Scientific breakthroughs often depend on discovering the meaning of seemingly random fluctuations.In his essay "On Noise," the 19th-century German philosopher Arthur Schopenhauer wrote that "the most eminent intellects have always been strongly averse to any kind of disturbance, interruption and distraction, and above everything to that violent interruption which is causedby noise." He was referring to audible sounds, in particular the "infernal cracking of whips… which paralyzes the brain."Scientists have a wider concept of noise, using the word to describe any kind of flfluctuation that has an element of randomness. Noise contrasts with signal, which is valuable because it conveys sought-after information. Separating interesting signals from obscuring noise is a big part of the art of experimental science and statistics.Sometimes, however, the noise is the signal. Two of Einstein's three great discoveries in his "miracle year" of 1905 involved learning from noise. Very recently, creative work with noise has once again powered a series of breakthrough discoveries in basic physics.Einstein traced the jitter of pollen grains, when immersed in flfluids and observed under a microscope, to their random encounters with individual flfluid molecules. This explanation enabled him to make a convincing case for the existence of molecules and to determine their masses. In his work on black body radiation, Einstein built on the work of Max Planck to show that graininess in the radiation's flflow means that light comes in lumps, or quanta. Today, we call the quanta of light photons.In everyday life, we usually think of an electric current as a smooth flflow. In fact, the flflow involves lumps of charge-electrons, usually-leading to an irreducible graininess in the current, known as shot noise. Shot noise becomes particularly noticeable for weak currents, and its strength can be used to measure an electron’s charge. In 1995, scientists used shot noise to show that in certain states of matter the granules of charge carry only a fraction of the charge of an electron, verifying a startling prediction of Robert Laughlin and opening up a thriving new fifield of "sub-electronics."Last month, the cover of Science announced that physicists had detected a new third kingdom of sub-electronic particle called anyons, which join the long-established bosons and fermions. Theorists have been looking forward to anyons for many years. (I named them in 1982.)The crucial observations here concern a more sophisticated version of shot noise, whichin volves not merely flfluctuations in a single current but correlations between flfluctuations in two of them. The new research opens up new worlds of possibilities, including the construction of more effffective quantum computers.Fluctuating currents and correlations among them might seem like pretty esoteric subjects, but they're a big part of the way we think, under the hood. Information in our brains is largely encoded in fifiring patterns of neurons, which are essentially spiky electric currents. Correlations among flfluctuations in the currents flflowing through difffferent neurons are the information-bearing patterns that embody perception and thought.Of course, noise can be noisome. The jumbled activation of injured nerves is involved in the pain of wounds or inflflammation. Epilepsy is a mind-storm of noise, and as Schopenhauer wrote, "a great intellect has no more power than an ordinary one as soon as it is interrupted, disturbed, distracted or diverted." But when noise is mined and harnessed, it can be a valuable resource.
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