Abstract

The Einstein-Podolsky-Rosen (EPR) [1] paradox was presented in 1935 as an argument that quantum mechanics is incomplete. The original EPR argument was formulated in terms of the position and momentum observables, which are continuous variables. Bohm later adapted EPR’s argument for a system with discrete variables [2], which motivated Bell to formulated his now well-known inequalities [3]. Bell showed that for certain ideal quantum systems the predictions of local hidden variable theories (constrained by “Bell inequalities”) are at variance with those of quantum mechanics. This result is known as Bells theorem. Nearly all experimental efforts have focussed on tests of Bells theorem [4]. To date these experiments have been hampered by low detector efficiences, preventing local realism from being irrefutably ruled out.

© 1996 Optical Society of America