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/ /FOR OFFI@IAI! WSE OHi!:¥ Another momentum-entangled EPR experiment was the 1998 Ph.D. thesis of Birgit Dopfer (Reference 17) performed at the University of Innsbruck and shown schematically in Figure 5. In the Dopfer experiment, moving a detector in one arm non locally changes the observed interference pattern in the other arm. Dopfer used 351 - nm UV pump radiation from an argon -ion laser with Type I down-conversion in a nonlinear Lil03 crystal cut with the optic axis at 90° to the pump beam to produce a pair of 702-nm momentum-entangled photons that emerged from the crystal at angles of 28.2° to the right and left of the pump axis, as shown in Figure 5. Figure 5. Schematic of the 1998 Dopfer Experiment (Reference 17) The lower entangled photon passed through a pair of slits and into a detector, while the upper photon passed through a lens that could image the two slits to perform a "which way" measurement if detector D2 was placed two focal lengths behind the lens (2f). However, if detector D2 was placed in a position one focal length behind the lens (f), the slits were not imaged, and light on the reflected line passing through either slit could reach the detector at the same points, producing a result similar to that of the Ghost Interference experiment. A structured two-sl it interference pattern could be switched on and off by moving a detector in the other arm of the experiment between the f and 2f positions. Again, from the viewpoint of nonlocal communication, it is noted that moving detector D2, which can be thought of as the action of a "sending" observer, nonlocally causes an observable change in the position distribution of the second photon, as detected at "receiver" position D1. However, the Dopfer experiment does not demonstrate nonlocal communication because, like the Ghost Interference experiment, it requires a classical communication link to impose the coincidence requirement between the detected photons because of the geometry of the experiment. Examination of these two experiments raises a very interesting question: Can the coincidence requirement be removed? The answer is not clear. In principle, the two entangled photons are connected by nonlocality whether they are detected in coincidence or not. The coincidence should therefore be removable. However, in both experiments the authors report that no two-slit interference distribution is observed 2f.. . . . . . . . . .. .. . . . . . . . . . . .. . .. . . .. . . .. . . . 702.2 nm 2f~ ~.. .. ... . .. .. ... . . . . . .... .. ........ . . ♦ -.. . ... . ........ . f Coincidence UNCLASSIFIED/ /FOA OFFI&il.t.l:: W&lii OHi!:¥ 9
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.