Mladen Pavicic
Institut für Theoretische Physik,
TU Berlin, Hardenbergstraße 36, D-10623 Berlin 12, Germany
Atominstitute of the Austrian Universities, Schüttelstraße 115, A-1020 Wien, Austria; pavicic@ati.ac.at
Department of Mathematics, University of Zagreb, GF, Kaciceva 26, POB-217, HR-10001 Zagreb, Croatia; mpavicic@faust.irb.hr; http://m3k.grad.hr/pavicic
Abstract. A nonclassical feature of the fourth order interference at a beam splitter, that genuine photon spin singlets are emitted in predetermined directions even when incident photons are unpolarized, has been used in a proposal for an experiment that imposes quantum spin correlation on truly independent photons. In the experiment two photons from two such singlets interfere at a beam splitter, and as a result the other two photons - which nowhere interacted and whose paths nowhere crossed - exhibit a 100% correlation in polarization, even when no polarization has been measured in the first two photons. The propsed experiment permits closure of the remaining loopholes in the Bell theorem proof, reveals the quantum nonlocality as a property of selection, and pioneers an experimental procedure for exact preparation of unequal superposition.
PACS numbers: : 42.50.Wm, 03.65.Bz
Keywords: four photon interferometry, quantum optics, quantum nonlocality, quantum teleportation, Bell experiment.