Documents / Official release
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//POil OFFI@IAk W&i 0NL¥ III. Nonlocality Versus Special Relativity? If nonlocal communication is possible, would it be in conflict with special relativity, with its well-known prohibition against faster-than-light signals? The answer is no. The prohibition of signals with superluminal speeds by Einstein's theory of special relativity is related to the fact that the definite simultaneity of two separated space time points is not Lorentz invariant. Since some hypothetical superluminal signal could be used to establish a fixed simultaneity relation between two such points-for example, by clock synchronization-this would imply a preferred inertial frame and would be inconsistent with Lorentz invariance and special relativity. In other words, it would be inconsistent with the even-handed treatment of all inertial reference frames in special relativity. However, if a nonlocal signal could be transmitted through measurements at separated locations performed on two entangled photons, the signal would be "sent" at the time of the arrival of the photon in one location and "received" at the time of arrival of the other photon. By varying path lengths to the two locations, these events could be made to occur in any order and time separation in any reference frame. Therefore, nonlocal signals (even superluminal and retrocausal ones) could not be used to establish a fixed simultaneity relation between two separated space-time points, because the sending and receiving of such signals do not have fixed time relations. The transmission and arrival instants of a nonlocal signal cannot be used for synchronization because the transmission and reception instants are path- and delay-dependent variables. To put it another way, the nonlocal connections of entangled photons lie along segmented lightlike world lines that transform properly under Lorentz transformations. Therefore, there is no conflict between nonlocal signaling and the Lorentz invariance of special re lativity. On the other hand, the principle of causality (cause must precede effect in all reference frames) appears very likely to be violated (or at least violate able) if nonlocal signaling is possible. Is it possible that the universe does have some preferred reference frame, perhaps that laid down by the cosmic microwave background or implied by Mach's Principle? Perhaps, but if such a preferred frame existed, its existence could not be established by nonlocal communication. IV. Momentum Domain Entanglement and EPR Experiments Einstein's original objection (Reference 4) that quantum mechanics appeared to be nonlocal was made with arguments based on a gedankenexperiment in the momentum domain. However, almost all of the modern EPR experiments testing the Bell Inequality and demonstrating quantum nonlocality have been performed in the polarization (that is, angular momentum) domain, usually with linearly polarized photons. Interestingly, it appears that if nonlocal quantum communication is possible at all, it may be more easily achieved in the momentum domain of Einstein's original focus. The optical process of spontaneous parametric down-conversion (Reference 15) turns out to be a very useful way of generating photon pairs entangled in either the polarization or the momentum domains. In this process, a photon from a "pump laser" UNCLASSIFIED/ /FOil OFFI&I.t.k W&li ONkY 5
Not linked to a story yet.
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.