Non-Additive Casimir Interactions on Fluid Interfaces

Abstract

Long-range van derWaals forces, or more generally Casimir interactions, are a result of quantum fluctuations of charges and electromagnetic fields, and play an important role in wetting and dewetting problems. Traditional approaches to studying fluid equilibrium problems employ additive approximations, includ- ing the Derjaguin and pairwise summation approximations to model the van der Waals forces. However, these additive approximations neglect important e ffects, including multiple scattering, material correlations and, in some cases, the eff ects of retardation ( finite speed of light). In this thesis, we introduce an approach for investigating fluid equilibrium problems that exploits recently developed, rigorous, and sophisticated techniques for computing Casimir forces in arbitrary geometries, with no approximations. As a proof-of-concept, we em- ploy these technique to present new predictions of fluid deformations in struc- tured, periodic gratings where non-additive e ffects not captured by pairwise- additive approximations become important, leading to dramatically diff erent predictions of wetting properties, e.g. wetting transitions and fluid shapes.