Realization of the Einstein-Podolsky-Rosen paradox for continuous variables
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±0.01, which is below the limit of unity required for the demonstration of the paradox.
©1992 The American Physical Society. Received 20 February 1992. We gratefully acknowledge the contributions of S. Braunstein, C. M. Caves, P. D. Drummond, J. L. Hall, and M. D. Reid. This work was supported by the Office of Naval Research, by the National Science Foundation, and by the Venture Research Unit of BP.