Optimal control of rotary motors
Abstract
Single-molecule experiments have found near-perfect thermodynamic efficiency in the rotary motor F1-ATP synthase. To help elucidate the principles underlying nonequilibrium energetic efficiency in such stochastic machines, we investigate driving protocols that minimize dissipation near equilibrium in a simple model rotary mechanochemical motor, as determined by a generalized friction coefficient. Our simple model has a periodic friction coefficient that peaks near system energy barriers. This implies a minimum-dissipation protocol that proceeds rapidly when the system is overwhelmingly in a single macrostate but slows significantly near energy barriers, thereby harnessing thermal fluctuations to kick the system over energy barriers with minimal work input. This model also manifests a phenomenon not seen in otherwise similar nonperiodic systems: Sufficiently fast protocols can effectively lap the system. While this leads to a trade-off between accuracy of driving and energetic cost, we find that our designed protocols outperform naive protocols.
- Publication:
-
Physical Review E
- Pub Date:
- January 2019
- DOI:
- 10.1103/PhysRevE.99.012119
- arXiv:
- arXiv:1807.10872
- Bibcode:
- 2019PhRvE..99a2119L
- Keywords:
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- Condensed Matter - Statistical Mechanics;
- Physics - Biological Physics;
- Quantitative Biology - Quantitative Methods
- E-Print:
- 12 pages, 11 figures