Casimir-Polder forces, boundary conditions and fluctuations

We review different aspects of atom–atom and atom–wall Casimir–Polder forces. We first discuss the role of a boundary condition on the interatomic Casimir–Polder potential between two ground-state atoms, and give a physically transparent interpretation of the results in terms of vacuum fluctuations and image atomic dipoles. We then discuss the known atom–wall Casimir–Polder force for ground- and excited-state atoms, using a different method which is also suited to extension to time-dependent situations. Finally, we consider the fluctuation of the Casimir–Polder force between a ground-state atom and a conducting wall, and discuss possible observation of this force fluctuation.