Can the Experiments Based on Parametric-Down Conversion Disprove Einstein Locality?

Abstract

The experiments on Einstein locality based on parametric-downconversion source are discussed. The theoretical analysis shows that this technique fails to discriminate between quantum mechanics and local realism. A deeper analysis of the standard approach shows that the Clauser-Horne factorizability of joint detection probability is not so general as to describe this type of source. A more adequate description of these photon pairs leads to define a new Bell-type inequality which is always satisfied by quantum mechanical predictions.