Defense Intelligence Reference Document The Space Communication Implications Of Quantum Entanglement

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determine the presence or absence of coherent interference, but this will not be
considered further here.)
A quantum sensitive cooled CCD camera is substituted for detector D1 of the Ghost
Interference experiment (Reference 11) and is set to measure distributions like those
shown in Figure 3. In the arrangement in Figure 7, switching the optical fiber routing
can be considered an act of transmitting a binary 0 or 1 signal. If the switch is in the
position leading to the outer detectors, then which-way information is available, and the
pattern detected by the camera should be a single-slit diffraction pattern labeled "1" in
Figure 7. If the switch is in the position leading to the combiner and middle detector,
waves from both slits contribute to the detection, no which-way information is
available, and the pattern detected by the camera should be the two-slit interference
pattern labeled "0" in Figure 7.
If the pattern observed by the camera can indeed be changed by switching the optical
fiber routing, then this would constitute a direct demonstration on nonlocal
communication. Such an observation would falsify the no-signal theorems mentioned
above, which require that in a noncoincidence scenario, no action on one entangled
photon can produce a "signal-capable" observable result at the detection of the other
entangled photon of the pair.
It should be emphasized that demonstrating nonlocal communication with momentum-
entangled photons, as described above, is not the same as actually sending a signal. It
should be clear that no real signal can be communicated with a single photon pair. Only
when multiple photons are detected can the underlying distribution function become
apparent. One can estimate that if the distribution functions to be distinguished are a
"pure" two-slit interference pattern modulated by a diffraction envelope and a "pure"
two-slit diffraction pattern, then about 10 photon detections would be required for a 3cr
decision between these two possibilities.
However, as mentioned in the previous section, it is likely that if nonlocal
communication is possible at all, it would have to be accomplished in a situation where
some compromise between entanglement and coherence has been achieved, and such
a compromise would inevitably cause the two patterns to be distinguished to be more
similar and more difficult to separate. Therefore, the 10 photon detections cited above
must be taken as a rather optimistic lower limit, and it is likely that a significantly larger
number of detections (perhaps ~100 or more) would be required. The time required to
send a single bit of information would then be the product of the photon detection rate
in the two arms of the experiment times the number of photons that must be detected
to receive the signal. In principle, such a transmission rate might be improved (and
fluorescence noise suppressed) by pulsing the pump laser, so that "clusters" of
entangled photons would be received with each such pulse.
VII. A Transactional Analysis of the Nonlocal
Communication Test
Now the transactional interpretation of quantum mechanics (Reference 19) to analyze
the system described above is used. The transactional interpretation describes the
formation of a quantum event as a three-stage process: (1) sending retarded "offer"
waves ('I') from emission location(s), (2) back-in-time responses from the reception
location(s) of advanced "confirmation" waves('!'*), and (3) the formation of a space-
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