Some Physical Consequences of Vacuum Polarization

The phenomenon of vacuum polarization can be studied apart from other higher-order electrodynamic effects through its modification of the electrostatic interaction of heavy charged particles. In particular the principal deviations of the $2p-1s$ level separations from the Bohr formula in light mu-mesonic atoms ($Z\le 6$) are expected to arise from vacuum polarization effects rather than relativistic effects (ordinary hydrogenic fine structure) or finite nuclear size. The vacuum polarization contribution to the electrostatic interaction of two protons requires slight changes in the usual analysis of proton-proton scattering data to obtain information about nuclear forces. The effect of vacuum polarization on the electrostatic energies of nuclei is also briefly discussed.