title: Giant Casimir effect in fluids in nonequilibrium steady states.
abstract: In this Letter, we consider the fluctuation-induced force exerted between two plates separated by a distance L in a fluid with a temperature gradient. We predict that for a range of distances L, this nonequilibrium force is anomalously large compared to other Casimir forces. The physical reason is that correlations in a nonequilibrium fluid are generally of longer range than other correlations, even than those near an equilibrium critical point. This giant Casimir force is related to a divergent Burnett coefficient that characterizes an Onsager cross effect between the pressure and the temperature gradient. The predicted Casimir force should be detectable with currently available experimental techniques.
authors.affiliation: Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20877, USA and Department of Physics, University of Maryland, College Park, Maryland 20877, 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 20877, USA.
authors.forename: J V
authors.initials: JV
authors.lastname: Sengers