2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/51612Exact calculations are given for the Casimir energy for various fields in $R\times S^3$ geometry. The Green's function method naturally gives a result in a form convenient in the high-temperature limit, while the statistical mechanical approach gives a form appropriate for low temperatures. The equivalence of these two representations is demonstrated. Some discrepancies with previous work are noted. In no case, even for ${\cal N}=4$ SUSY, is the ratio of entropy to energy found to be bounded.9 pages, no figures, requires sc3conf.styHigh Energy Physics - Theorytext