The noiseless limit of a thermal ratchet device using ferrofluids is studied in detail. Contrary to previous claims it is proved that no directed transport can occur in this model in the absence of fluctuations.
@article{arxiv.cond-mat/0411060,
title = {Noiseless limit of a ferrofluid ratchet},
author = {Volker Becker and Andreas Engel},
journal= {arXiv preprint arXiv:cond-mat/0411060},
year = {2009}
}