Experimental investigations of stochastic thermodynamics

大约150年前，麦克斯韦第一次提出了这样一个问题：当一个“手指整洁的生物”--一个恶魔--利用信息从热量中做功时，会发生什么？ 热力学第二定律应该禁止这样做，但怎么做呢？ 这个问题困扰了物理学家，并引发了长达世纪的争论。一年前，在我的实验室里，我们做了一个明确的测量，证实了50年前提出的一个假设：麦克斯韦恶魔需要擦除信息，而擦除信息需要消耗尽可能多的能量。 这里提出的工作追求这些想法的情况下，系统是不平衡的。 一个重要的目标是能够测量函数的形式，该函数描述了一个系统的熵。 有人提出，但从未直接测试过，香农熵扮演了这个角色。 这个函数表面上看起来像是世纪标准的吉布斯-玻尔兹曼熵表达式，但它不适用于平衡态。

Nearly 150 years ago, Maxwell first asked what happens when a “neat fingered being” a demon uses information to extract work from heat. The Second Law of Thermodynamics should forbid this, but how? The question has galled physicists and provoked debate for over a century. One year ago in my laboratory, we made a definitive measurement that confirms a hypothesis proposed 50 years ago: that Maxwell demons need to erase information and that erasing information requires dissipating as much energy as is gained. The work proposed here pursues these ideas to cases where systems are out of equilibrium. One important goal is to be able to measure the form of the function that describes the entropy of a system out of equilibrium. It has been proposed, but never directly tested, that the Shannon entropy plays this role. The function superficially looks like the standard 19th century Gibbs-Boltzmann expression for the entropy but applies out of equilibrium.