van der Waals interaction potential between Rydberg atoms near surfaces

van der Waals interactions, as a result of the exchange of photons between particles, can be altered by modifying the environment through which these photons propagate. As a consequence, phenomena such as the Rydberg blockade mechanism between highly excited atoms or excitons can be controlled by adding reflecting surfaces. We provide the quantum electrodynamic framework for the van der Waals interaction in the nonretarded limit that is relevant for long-wavelength transitions, such as those between Rydberg systems, and show its intimate connection with common static dipole-dipole interactions, thereby providing a generalization to include macroscopic bodies.