Realization of the Einstein-Podolsky-Rosen paradox for continuous variables

Abstract

The Einstein-Podolsky-Rosen paradox is demonstrated experimentally for dynamical variables having a continuous spectrum. As opposed to previous work with discrete spin or polarization variables, the continuous optical amplitudes of a signal beam are inferred in turn from those of a spatially separated but strongly correlated idler beam generated by nondegenerate parametric amplification. The uncertainty product for the variances of these inferences is observed to be 0.70\ifmmode\pm\else\textpm\fi{}0.01, which is below the limit of unity required for the demonstration of the paradox.