10.11.2015 - Pablo Barcellona - On the impact of dissipation on dispersion interactions between two atoms

More than 60 years after their prediction, Casimir and Casimir--Polder forces are nowadays measured with high precision. Yet two very fundamental questions remain unanswered: the persisting discrepancies between Casimir-force measurements and theory and the oscillatory behavior (or not) of the van der Waals force between two atoms, at least one of them excited, in the Casimir-Polder (retarded) regime. Our dynamical theory suggests that the influence of radiative damping is suppressed in the Casimir--Polder interaction between two atoms in thermal equilibrium; and it uniquely predicts a spatially oscillating force between excited atoms or molecules. The former result may have implications for the Casimir force where the proposed use of the plasma model for the response of conduction electrons in metals also implies a reduced influence of damping.