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Updated: Aug 13, 2026

Biophysical Characterization of Flagellar Motor Functions
Published on: January 18, 2017
Performance characteristics of Brownian motors
Heiner Linke1, Matthew T Downton, Martin J Zuckermann
1Materials Science Institute and Physics Department, University of Oregon, Eugene, OR 97405, USA. linke@uoregon.edu
Abstract:
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.
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