2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/139681We argue that the appropriate variable to study a non trivial geometry dependence of the Casimir force is the lateral component of the Casimir force, which we evaluate between two corrugated metallic plates outside the validity of the Proximity Force Approximation (PFA). The metallic plates are described by the plasma model, with arbitrary values for the plasma wavelength, the plate separation and the corrugation period, the corrugation amplitude remaining the smallest length scale. Our analysis shows that in realistic experimental situations the Proximity Force Approximation overestimates the force by up to 30%.4 pages. Identical to v1, which was accidentally replaced by a different paper (quant-ph/0610026)Quantum PhysicsHigh Energy Physics - TheoryLateral Casimir force beyond the Proximity Force Approximationtext