ON THE EXPERIMENTAL VIOLATION OF MERMIN'S INEQUALITY WITH IMPERFECT MEASUREMENTS

We investigate theoretically the feasibility of an experimental test of the Bell-type inequality derived by Mermin for correlated spins larger than 1/2. Using the Schwinger representation, we link the output fields of two two-mode squeezers in order to create correlated effective spins between two observers. Spin measurements will be performed by photon-number-resolved photodetection, which has recently come of age. We examine the effect of nonideal detection quantum efficiency and any other optical loss on the violation margin of Mermin's inequality. We find that experimental violation is well accessible for spins larger than 1, for quantum efficiencies compatible with the current state of the art.