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Entangled photons, nonlocality and Bell inequalities in the undergraduate laboratory

Dietrich Dehlinger·M. W. Mitchell
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Abstract

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. The polarization state of the photons is tunable. Using an entangled state analogous to that described in the Einstein-Podolsky-Rosen ``paradox,'' we demonstrate strong polarization correlations of the entanged photons. Bell's idea of a hidden variable theory is presented by way of an example and compared to the quantum prediction. A test of the Clauser, Horne, Shimony and Holt version of the Bell inequality finds $S = 2.307 \pm 0.035$, in clear contradiciton of hidden variable theories. The experiments described can be performed in an afternoon.

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Dietrich Dehlinger, M. W. Mitchell. 2002-05-27. Entangled photons, nonlocality and Bell inequalities in the undergraduate laboratory. https://doi.org/10.1119/1.1498860

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