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Violation of Cauchy-Schwarz Inequality in the Macroscopic Regime



Alberto M. Marino, V Boyer, Paul D. Lett


We have observed a violation of the Cauchy-Schwarz inequality in the macroscopic regime by more than 8 standard deviations. The violation has been obtained while filtering out only the low frequency noise of the quantum-correlated beams that results from the technical noise of the laser used to generate them. We use bright intensity-difference squeezed beams produced by four-wave mixing as the source of correlated fields. We also show that squeezing does not necessarily imply a violation of the Cauchy-Schwarz inequality.
Physical Review Letters


alkali vapor, classical inequality, electromagnetically-induced transparancy, four-wave mixing, nonclassical light, squeezed light


Marino, A. , Boyer, V. and Lett, P. (2008), Violation of Cauchy-Schwarz Inequality in the Macroscopic Regime, Physical Review Letters, [online], (Accessed July 14, 2024)


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Created June 10, 2008, Updated February 17, 2017