2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/93394We analyse interaction-free measurements on classical and quantum objects. We show the transition from a classical interaction free measurement to a quantum non-demolition measurement of atom number, and discuss the mechanism of the enforcement of complementarity in atom interferometric interaction-free measurements.4 pages REVTEX, one eps file with 4 figuresQuantum Physicstext