Improved Effective Range Expansion for Casimir-Polder potential

We study the effective range expansion of scattering on a real Casimir-Polder potential. We use Liouville transformations which transform the potential landscape while preserving the reflection and transmission amplitudes. We decompose the scattering calculation in two more elementary problems, one for the homogeneous 1/z^4 potential and the other one for the correction to this idealization. We use the symmetries of the transformed problem and the properties of the scattering matrices to derive an improved effective range expansion leading to a more accurate expansion of scattering amplitudes at low energy

Casimir torque between nanostructured plates

We investigate in detail the Casimir torque induced by quantum vacuum fluctuations between two nanostructured plates. Our calculations are based on the scattering approach and take into account the coupling between different modes induced by the shape of the surface which are neglected in any sort of proximity approximation or effective medium approach. We then present an experimental setup aiming at measuring this torque.Comment: 7 pages, 7 figure

Fluctuations of the Casimir potential above a disordered medium

We study the statistical fluctuations of the Casimir potential felt by an atom approaching a dielectric disordered medium. Starting from a microscopic model for the disorder, we calculate the variance of potential fluctuations in the limit of a weak density of heterogeneities. We show that fluctuations are essentially governed by scattering of the radiation on a single heterogeneity, and discuss in which limits they become larger than the average value predicted by effective medium theory. Finally, for denser disorder we show that multiple scattering processes become relevant.Comment: 9 pages, 5 figure