2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/126059We show how Bell observables on a bipartite quantum system can be obtained by local observables via a controlled-unitary transformation. For continuous variables this result holds for the Bell observable corresponding to the non-conventional heterodyne measurement on two radiation modes, which is connected through a 50-50 beam-splitter to two local observables given by single-mode homodyne measurements. A simple scheme for a controlled-unitary transformation of continuous variables is also presented, which needs only two squeezers, a parametric downconverter and two beam splitters.9 pages, elsart, 1 figureQuantum Physicstext