NN vacuum polarizations and meson exchange interactions in finite nuclei

First we solve the relativistic Hartree problem for a finite nucleus: We obtain the relativistic single particle states of positive and negative energy nucleons in 16O, treating these nucleons on the equal footing, and compare the results with those of the mean field theory. We solve the simultaneous mean field equations as matrix equations on the wave packet basis. This method needs not rely on the derivative expansion to renormalize the divergent sums of the densities and of the energies of negative energy nucleons. The contribution of these nucleons suppresses the mean meson fields and increases the nuclear radius. Secondly, taking the positive energy nucleon state sector picture of a nucleus to elucidate the results of the above relativistic Hartree calculation, we derive the effective nuclear interactions between positive energy nucleons which are corrected by the NN vacuum polarizations. The polarizations suppress the meson exchange interactions and increase their ranges. (orig.)