Europhys. Lett.
Volume 68, Number 6, December 2004
Page(s) 776 - 782
Section General
Published online 12 November 2004
Europhys. Lett., 68 (6), pp. 776-782 (2004)
DOI: 10.1209/epl/i2004-10275-5

Forces induced by nonequilibrium fluctuations: The Soret-Casimir effect

A. Najafi and R. Golestanian

Institute for Advanced Studies in Basic Sciences - Zanjan 45195-159, Iran

received 9 August 2004; accepted in final form 14 October 2004
published online 12 November 2004

The notion of fluctuation-induced forces is generalized to the cases where the fluctuations have nonequilibrium origin. It is shown that a net force is exerted on a single flat plate that restricts scale-free fluctuations of a scalar field in a temperature gradient. This force tends to push the object to the colder regions, which is a manifestation of thermophoresis or the Soret effect.

05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.
82.70.-y - Disperse systems; complex fluids.
05.70.Jk - Critical point phenomena.

© EDP Sciences 2004