VACUUM FLUCTUATION AND RETARDATION EFFECTS ON LONG-RANGE POTENTIALS

The Casimir-Polder R-7 retarded potential between two neutral (polarizable) atoms at a separation R, which replaces the nonrelativistic R-6 van der Waals potential for R sufficiently large, has been derived both by standard techniques and by assuming the atoms to be within a large volume with conducting walls and considering vacuum-fluctuation effects. The latter technique is here used to provide simple derivations of the R-5 potential between a charged point particle and a polarizable system-an addition to the usual R-4 polarization potential-and the R-3 two-photon contribution to the potential between two charged point particles. It also suggests a new, R-2 potential-an addition to the usual R-1 image potential-between a charged point particle and a conducting wall. © 1978 The American Physical Society.