2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/56298We apply general formalism of quantum field theory and addition theorem for Bessel functions to derive formula for the Casimir-Polder energy of interaction between a polarizable particle and a dilute dielectric ball and Casimir energy of a dilute dielectric ball. The correspondence between the Casimir-Polder formula and Casimir energy of a dilute dielectric ball is shown. Different approaches to the problem of Casimir energy of a dielectric ball are reviewed and analysed by use of addition theorem for Bessel functions.9 pages, no figures, Latex 2e, different approaches are reviewed and analysed in the Conclusions section ; explanations are addedHigh Energy Physics - Theorytext