title: Field-driven crossover from attractive-to-repulsive Casimir-like force in smectic films.
abstract: External fields have a profound effect on the fluctuations of strongly correlated fluids, such as a liquid crystal. Within a harmonic functional integral approach, we compute the fluctuation-induced force between the surfaces of a smectic liquid-crystal film under the presence of an ordering field. In particular, we show that for asymmetrically anchored films, the thermal Casimir interaction energy can be collapsed into a universal form crossing over from a repulsive to an attractive interaction as the film thickness is increased. We discuss the possible relevance of this field effect in nematic-smectic wetting transitions.
authors.affiliation: Departamento de Física, Universidade Federal de Alagoas, 57072-970 Maceió-AL, Brazil.
authors.forename: I N
authors.initials: IN
authors.lastname: de Oliveira
authors.forename: M L
authors.initials: ML
authors.lastname: Lyra