AAWSAP DIRD, The Space Communication Implications of Quantum Entanglement and Nonlocality, March 2010

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implications of this dichotomy are considered in the context of the "no-signal"
theorems.
It is noted that there is some misinformation in the literature concerning the chronology
of successful EPR polarization correlation experiments, and here we wish to set the
record at least somewhat straighter. The experimental measurement that first
demonstrated a polarization correlation related to EPR nonlocality was performed by C.
S. Wu and I. Shanknov in 1949 (Reference 7), well before Bell's work and the
subsequent interest in testing Bell's Inequality. Wu and Shanknov showed that the
linear polarizations of back-to-back entangled gamma rays from electron-positron
annihilation (an L=O negative parity state) were anticorrelated, for example, if one
photon was polarized vertically, then the other was polarized horizontally. They did not,
however, investigate the falloff of the correlation with polarimeter angle, which is the
basis of Bell Inequality tests, nor did they depict their results as a consequence of
quantum nonlocality.
Almost two decades passed before the publication of John Bell's pivotal work (Reference
8) in 1964 and 1966. In 1972, Freedman and Clauser (Reference 1) performed the first
definitive Bell inequality test by measuring the polarization correlation of entangled
photons from a positive parity L=O atomic cascade in calcium. Their results were in
agreement with the predictions of quantum mechanics and were inconsistent with local
hidden-variable theories by 6. 7 standard deviations. A decade later, in 1982, EPR
measurements of the Aspect group (Reference 2) eliminated several "loophole"
scenarios that might constitute unlikely ways of preserving classical locality and again
demonstrated agreement with quantum mechanics and inconsistency with local hidden­
variable theories, this time by 46 standard deviations. In a more recent example of an
EPR experiment, the Gisin group (Reference 9) used the fiber-optic cables owned by the
Swiss Telephone System to demonstrate the nonlocal connection between EPR
measurements made at locations in Geneva and Bern, Swiss cities with a line-of-sight
separation of 156 km-a direct demonstration, if one was required, that quantum
nonlocality can operate over quite large distances.
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Figure 1. Schematic of the 1972 Freedman-Clauser Experiment (Reference 1)
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