Bell's inequality violation for entangled generalized Bernoulli states   in two spatially separate cavities
  We consider the entanglement of orthogonal generalized Bernoulli states in two separate single-mode high-$Q$ cavities. The expectation values and the correlations of the electric field in the cavities are obtained. We then define, in each cavity, a dichotomic operator expressible in terms of the field states which can be, in principle, experimentally measured by a probe atom that ``reads'' the field. Using the quantum correlations of couples of these operators, we construct a Bell's inequality which is shown to be violated for a wide range of the degree of entanglement and which can be tested in a simple way. Thus the cavity fields directly show quantum non-local properties. A scheme is also sketched to generate entangled orthogonal generalized Bernoulli states in the two separate cavities. 
R. Lo Franco, G. Compagno, A. Messina, A. Napoli