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This Defense Intelligence Reference Document, dated 30 March 2010, was prepared by the Defense Intelligence Agency's Defense Warning Office under its Advanced Aerospace Weapon System Applications Program. It reviews quantum entanglement, nonlocality and EPR experiments, and asks whether nonlocal quantum effects could carry observer-to-observer signals faster than light. The paper describes proposed experiments and an example of real-time Earth control of a Mars rover. It concludes that there is no compelling answer yet and that experimental tests are needed.
From the source: Release of 2026-09-18 Incident: 3/30/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD reviews quantum entanglement and nonlocality with a focus on whether those phenomena might be usable as a means of faster-than-light communication between observers, especially for real-time space operations over interplanetary distances. The report surveys the relevant quantum experiments and no-signal theorems, then examines proposed communication schemes based mainly on momentum-entangled photons, including scenarios involving superluminal and retro-causal signaling. However, it repeatedly acknowledges that the central question remains unresolved experimentally, and it gives substantial attention to the coherence-versus-entanglement tradeoff and other features of standard quantum mechanics that may prevent usable signaling even if non-local correlations are experimentally validated. Overall, the document is an exploratory analysis of whether quantum nonlocality could conceivably support a practical communications application rather than a demonstration of prospective utility.
UNCLASSIFIED/ /POK OFFICIAL tt.!I!! 8HL'f Do these EPR experiments constitute a demonstration of the existence of quantum nonlocality? There is more than one way of interpreting the implications of the experimental results (Reference 1, 2), and one can find much discussion in the literature as to whether it is locality or "realism" (the objective observer- independent reality of external events) that has been refuted by these EPR measurements. Noble Laureate Anthony Leggett of the University of Illinois recently pushed this issue somewhat further (Reference 10). He demonstrated that by focusing on the falloff of correlations with elliptical polarization rather than the linear polarization used in the Bell Inequality EPR experiments, one can compare the predictions of quantum mechanics with a class of nonlocal realistic theories that he constructed. The resulting Leggett Inequalities can be used in the same way as the Bell Inequalities, but to test theories incorporating nonlocal realism instead of local realism. Anton Zeilinger's group at the Institute for Quantum Optics and Quantum Information (IQOQI) in Vienna performed a definitive test of the Leggett Inequalities (Reference 11). The results show that using elliptically polarized entangled photons, the Leggett Inequalities in two observables are violated by 3.6 and by 9 standard deviations. This is interpreted as a statistically significant falsification of the whole class of nonlocal realistic theories constructed by Leggett. The IQOQI group summarizes its results with the statement "We believe that our results lend strong support to the view that any future extension of quantum theory that is in agreement with experiments must abandon certain features of realistic descriptions." It is our view, however, that this is mainly an exercise in demolishing a "strawman." Leggett's nonlocal realistic theories assume that when entangled photons emerge from their emission source, they are in a definite state of polarization. It is well known that when that assumption (and no others) is made, one does not observe the quantum mechanical prediction of Malus's Law for the correlations of the photon pair. However, Leggett solves that problem by assuming an unspecified nonlocal connection mechanism between the detection systems that fixes the discrepancy. In effect, the two measurements talk to each other nonlocally in such a way that the detected linea rly polarized photons obey Malus's Law and produce the same linear polarization correlations predicted by quantum mechanics calculations. Leggett then shows that this nonlocal "fix" cannot be extended into the realm of elliptical polarization, and that quantum mechanics and this type of nonlocal realistic theories give differing predictions for the elliptic polarization correlations. In other words, the "reality" that is being tested is whether the photon source is initially emitting the entangled photons in a definite state of polarization. It is this version of "reality" that has been falsified by the IQOQI measurements. It is our view that this assumption, clearly inconsistent with the formalism of quantum mechanics, is invalid, and that nature is both nonlocal and unrealistic, if by realism one means that when entangled photons emerge from their emission source, they are in a definite state of polarization. This very restricted definition of realism is not required, and it is assumed that the intrinsic nonlocality of standard quantum mechanics is a physical fact. It is noted that the several polarization bases used in t hese ki nds of polarization EPR experiments make demonstrating the quantum nonlocal connections straightforward but also make it effectively impossible to use those connections for observer-to- UNCLASSIFIED/ /FOR: OFFI&il.t.k W&liii OP•k¥ 3
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 32 pages are in the text index: search them above, or from the library's search.