2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/187967We consider a multigravity approach to spacetime foam. As an application we give indications on the computation of the cosmological constant, considered as an eigenvalue of a Sturm-Liouville problem. A variational approach with Gaussian trial wave functionals is used as a method to study such a problem. We approximate the equation to one loop in a Schwarzschild background and a zeta function regularization is involved to handle with divergences. The regularization is closely related to the subtraction procedure appearing in the computation of Casimir energy in a curved background. A renormalization procedure is introduced to remove the infinities together with a renormalization group equation.6 pages. Talk given at IRGAC-2006 (Barcelona, July 11-15, 2006), accepted for publication in Journal of Physics A and extended version of the talk given at MG11, Berlin, 23-29 July, 2006General Relativity and Quantum CosmologyHigh Energy Physics - Theorytext