Entangled photons, nonlocality, and Bell inequalities in the undergraduate laboratory

摘要: We use polarization-entangled photon pairs to demonstrate quantum nonlocality in an experiment suitable for advanced undergraduates. The photons are produced by spontaneous parametric downconversion using a violet diode laser and two nonlinear crystals. polarization state of the is tunable. Using entangled analogous that described Einstein–Podolsky–Rosen paradox, we strong correlations photons. Bell’s idea hidden variable theory presented way example compared prediction. A test Clauser, Horne, Shimony, Holt version Bell inequality finds S=2.307±0.035, clear contradiction theories. experiments can be performed afternoon.