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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. OFFl@IAL l!ISE 8PU::Y interacts with a nonlinear crystal and is transformed into two photons with energies and vector momenta that add up to those of the original pump photon. Depending on the type of down-conversion process, there are well-defined polarization correlations between the entangled photons. The down-converted photons may also be easily prepared in momentum -entangled states, because within the nonlinear medium, the vector momenta of the down-converted pair of photons must add to give that of the pump photon. The first measurement using momentum-entangled down-conversion photons that might be related to nonlocal communication is the Ghost Interference experiment reported in 1995 by the Shih group (Reference 16), shown schematically in Figure 2. The experimenters used degenerate collinear Type-II down-conversion of 351-nm UV pump radiation from an argon-ion laser passed through a 3- mm-long BBO (f3-BaB2Q4) crystal that 0 had been cut with the optic axis at a phase-matching angle of 42.2° to the pump beam to produce a pair of collinear momentum-entangled 702-nm photons with opposite polarizations. The entangled photons emerge from the crystal very nearly parallel with the pump beam. The pump beam is then split off from the pair using refraction in a quartz prism (UV Prism), and the entangled photons are separated with a polarization-selecting beam splitter (BS) that reflects the "extraordinary" vertically polarized photon (e) and Figure 2. Schematic of the 1995 Ghost Interference transmits the "ordinary" horizontally Experiment (Reference 16) of the Shih group polarized photon (o) . Both photons are passed through 702 ± 10-nm wavelength-selective filters (f1,2) and then detected (D1,2). 35 1 nm Ar Laser BS f Slits 1 fiber Gating Gated UNCLASSIFIED/ /FOR. OFFICIJ!IL U:!~ Gilt I 6
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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.