title: Nonequilibrium Casimir-like Forces in Liquid Mixtures.
abstract: In this Letter, we consider a liquid mixture confined between two thermally conducting walls subjected to a stationary temperature gradient. While in a one-component liquid nonequilibrium fluctuation forces appear inside the liquid layer, nonequilibrium fluctuations in a mixture induce a Casimir-like force on the walls. The physical reason is that the temperature gradient induces large concentration fluctuations through the Soret effect. Unlike temperature fluctuations, nonequilibrium concentration fluctuations are also present near a perfectly thermally conducting wall. The magnitude of the fluctuation-induced Casimir force is proportional to the square of the Soret coefficient and is related to the concentration dependence of the heat and volume of mixing.
authors.affiliation: Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA.|Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Kirkpatrick
authors.affiliation: Departamento de Física Aplicada I, Facultad de Física, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Ortiz de Zárate
authors.affiliation: Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: J V
authors.initials: JV
authors.lastname: Sengers