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Proceedings Paper

Detailed balance of the Feynman micromotor
Author(s): Derek Abbott; Bruce R. Davis; Juan M. R. Parrondo
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Paper Abstract

One existing implication of micromotors is that they can be powered by rectifying non-equilibrium thermal fluctuations or mechanical vibrations via the so-called Feynman- micromotor. An example of mechanical rectification is found in the batteryless wristwatch. The original concept was described in as early as 1912 by Smoluchowski and was later revisited in 1963 by Feynman, in the context of rectifying thermal fluctuations to obtain useful motion. It has been shown that, although rectification is impossible at equilibrium, it is possible for the Feynman-micromotor to perform work under non-equilibrium conditions. These concepts can now be realized by MEMS technology and may have exciting implications in biomedicine - where the Feynman- micromotor can be used to power a smart pill, for example. Previously, Feynman's analysis of the motor's efficiency has been shown to be flawed by Parrondo and Espanol. We now show there are further problems in Feynman's treatment of detailed balance. In order to design and understand this device correctly, the equations of detailed balance must be found. Feynman's approach was to use probabilities based on energies and we show that this is problematic. In this paper, we demonstrate corrected equations using level crossing probabilities instead. A potential application of the Feynman-micromotor is a batteryless nanopump that consists of a small MEMS chip that adheres to the skin of a patient and dispense nanoliter quantities of medication. Either mechanical or thermal rectification via a Feynman- micromotor, as the power source, is open for possible investigation.

Paper Details

Date Published: 29 September 1999
PDF: 6 pages
Proc. SPIE 3891, Electronics and Structures for MEMS, (29 September 1999); doi: 10.1117/12.364437
Show Author Affiliations
Derek Abbott, Univ. of Adelaide (Australia)
Bruce R. Davis, Univ. of Adelaide (Australia)
Juan M. R. Parrondo, Univ. Complutense de Madrid (Spain)

Published in SPIE Proceedings Vol. 3891:
Electronics and Structures for MEMS
Neil W. Bergmann; Olaf Reinhold; Norman C. Tien, Editor(s)

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