Molecular motor with a build-in escapement device
Abstract
We study dynamics of a classical particle in a one-dimensional potential, which is composed of two periodic components, that are time-independent, have equal amplitudes and periodicities. One of them is externally driven by a random force and thus performs a diffusive-type motion with respect to the other. We demonstrate that here, under certain conditions, the particle may move unidirectionally with a constant velocity, despite the fact that the random force averages out to zero. We show that the physical mechanism underlying such a phenomenon resembles the work of an escapement-type device in watches; upon reaching certain level, random fluctuations exercise a locking function creating the points of irreversibility in particle's trajectories such that the particle gets uncompensated displacements. Repeated (randomly) in each cycle, this process ultimately results in a random ballistic-type motion. In the overdamped limit, we work out simple analytical estimates for the particle's terminal velocity. Our analytical results are in a very good agreement with the Monte Carlo data.
Cite
@article{arxiv.cond-mat/0312488,
title = {Molecular motor with a build-in escapement device},
author = {G. Oshanin and J. Klafter and M. Urbakh},
journal= {arXiv preprint arXiv:cond-mat/0312488},
year = {2007}
}
Comments
7 pages, 4 figures