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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/ /FOR OFFI@IAk WSE OPtklf observer signaling (Reference 12), because one would need to deduce from the arriving photons the polarization basis that was being used in the distant measurements. This is an aspect of the parameter independence mentioned above. While each observer is free to choose a parameter that specifies the polarization basis (for example, circular right/left, linear at any angle) for the measurement, he is not free to force the photon into a particular state of that basis, as would be required for nonlocal communication. However, measuring polarization correlations in a system with angular momentum constraints is not the only way to demonstrate the nonlocal connection between the entangled separated parts of a quantum system. Below, EPR experiments that use momentum entanglement are discussed, and the question of whether such quantum systems might provide a better vehicle for observer-to-observer nonlocal communication is explored, because by using momentum entanglement, an observer is able to force the photon into particle-like or wave-like behavior. II. The Quantum No-Signal Theorems As Einstein implied with his well-known "spooky actions at a distance" comment, enforcement of quantum correlations across spacelike and negative timelike intervals by nonlocality is very counterintuitive. It appears to imply the twin possibilities of superluminal commun ication and of reverse causation through back-in-time communication between observers. However, a number of authors (Reference 13) have presented "proofs" that such nonlocal observer-to-observer communication is impossible within the formalism of standard quantum mechanics. These theorems assert that in separated measurements involving entangled quantum systems, the quantum correlations will be preserved, but there will be no effect apparent to an observer in one sub-system if the character of the measurement is changed in the other sub-system . Thus, it is asserted, nonlocal signaling is impossible. As mentioned above, EPR experiments can be viewed (Reference 5, 6) as demonstrating violations of outcome independence or parameter independence or both. Outcome independence cannot be used for nonlocal signaling, while parameter independence can. Thus, any test of nonlocal signaling is, in effect, a test of the parameter independence of quantum phenomena, and the no-signal theorems are "proofs" of parameter independence. Do these no-signal "proofs" really have the status of mathematical theorems? Perhaps not. Recently it has been pointed out (Reference 14) that at least some of these "proofs" ruling out nonlocal signaling are tautological, assuming that the measurement process and its associated Hamiltonian are local, thereby building the final conclusion of no signaling into their starting assumptions. Standard quantum mechanical Bose Einstein symmetrization in systems of bosons has been raised as a counter-example, shown to be inconsistent with the initial assumptions of some of these "proofs." Therefore, at least from some perspectives, the possibility of nonlocal communication in the context of standard quantum mechanics remains open and appropriate for experimental testing. UNCLASSIFIED/ /FOR OFFI@IAk WSE OHkl/ 4
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