title: Direct calculation of the critical Casimir force in a binary fluid.
abstract: We show that critical Casimir effects can be accessed through direct simulation of a model binary fluid passing through the demixing transition. We work in the semi-grand-canonical ensemble, in slab geometry, in which the Casimir force appears as the excess of the generalized pressure, P_{⊥}-nμ. The excesses of the perpendicular pressure, P_{⊥}, and of nμ, are individually of much larger amplitude. A critical pressure anisotropy is observed between forces parallel and perpendicular to the confinement direction, which collapses onto a universal scaling function closely related to that of the critical Casimir force.
authors.affiliation: Université de Lyon, Laboratoire de Physique, École normale supérieure de Lyon, CNRS, UMR5672, 46 Allée d'Italie, 69364 Lyon, France.
authors.forename: Francesco
authors.initials: F
authors.lastname: Puosi
authors.affiliation: Université de Lyon, Laboratoire de Physique, École normale supérieure de Lyon, CNRS, UMR5672, 46 Allée d'Italie, 69364 Lyon, France.
authors.forename: David Lopes
authors.initials: DL
authors.lastname: Cardozo
authors.affiliation: Université de Lyon, Laboratoire de Physique, École normale supérieure de Lyon, CNRS, UMR5672, 46 Allée d'Italie, 69364 Lyon, France.
authors.forename: Sergio
authors.initials: S
authors.lastname: Ciliberto
authors.affiliation: Université de Lyon, Laboratoire de Physique, École normale supérieure de Lyon, CNRS, UMR5672, 46 Allée d'Italie, 69364 Lyon, France.
authors.forename: Peter C W
authors.initials: PC
authors.lastname: Holdsworth