Linke Heiner, Downton Matthew T, Zuckermann Martin J
Materials Science Institute and Physics Department, University of Oregon, Eugene, OR 97405, USA.
Chaos. 2005 Jun;15(2):26111. doi: 10.1063/1.1871432.
Brownian motors are nonequilibrium systems that rectify thermal fluctuations to achieve directed motion, using spatial or temporal asymmetry. We provide a tutorial introduction to this basic concept using the well-known example of a flashing ratchet, discussing the micro- to nanoscopic scale on which such motors can operate. Because of the crucial role of thermal noise, the characterization of the performance of Brownian motors must include their fluctuations, and we review suitable performance measures for motor coherency and efficiency. Specifically, we highlight that it is possible to determine the energy efficiency of Brownian motors by measuring their velocity fluctuations, without detailed knowledge of the motor function and its energy input. Finally, we exemplify these concepts using a model for an artificial single-molecule motor with internal degrees of freedom.
布朗运动马达是非平衡系统，利用空间或时间不对称性来纠正热涨落以实现定向运动。我们以著名的闪烁棘轮为例，对这一基本概念进行教程式介绍，讨论此类马达能够运行的微观到纳米尺度。由于热噪声的关键作用，布朗运动马达性能的表征必须包括其涨落情况，我们回顾了适用于马达相干性和效率的性能度量。具体而言，我们强调，在无需详细了解马达功能及其能量输入的情况下，通过测量其速度涨落就有可能确定布朗运动马达的能量效率。最后，我们用一个具有内部自由度的人工单分子马达模型来例证这些概念。
