Electromagnetic Casimir densities in dielectric spherical media

Local expectation values of the electromagnetic energy density, and of the quantity 1/4G2 = 1/2(HxB-ExD), are calculated both inside and outside a spherical surface dividing two media of permeabilities μ1 and μ2. In both media the relationship epsilon-cμ = 1 is assumed, where epsilon-c is the permittivity. The powerful source theory method is used. The results are displayed graphically, although analytical approximate expressions for the field densities are obtained near the surface. The formalism is general enough to describe QED and QCD cavities (to zeroth order in the gauge coupling constant) on the same footing, as limiting cases. Retaining the cutoff parameter at a finite value, it is finally shown how the large interior and exterior cutoff terms compensate each other in the global Casimir energy