DOW-UAP-D133: The Space-Communication Implications of Quantum Entanglement and Nonlocality - Ghost Interference, Retrocausal Signals and a Real-Time Mars Rover

Source file: DOW-UAP-D133_AAWSAP-DIRD-The-Space-Communication-Implications-of-Quantum-Entanglement-and-Nonlocality-March-30-2010.pdf Originating agency: Defense Intelligence Agency (DIA), Defense Warning Office, under the AAWSA Program Document type: Defense Intelligence Reference Document (DIRD), "Acquisition Threat Support" series; control number DIA-08-1003-016 Date: 30 March 2010 (information cutoff date, ICOD: 1 December 2009) Classification: UNCLASSIFIED//FOR OFFICIAL USE ONLY (the FOR OFFICIAL USE ONLY caveat is struck through on every page; released 2026) Page count: 32 VIRIN: 260918-D-D0360-1122 PURSUE Release: 6

Summary

DOW-UAP-D133 asks one question: can quantum entanglement, the linked behaviour of particles born in the same event, be used to send a message? If it could, the paper argues, it would be "an enabling technology for superluminal (and retrocausal) signaling," with the most obvious use in space, where the speed of light makes real-time control of distant probes impossible. The author appears only as the redacted pseudonym AAP Person 76.

The paper is more technical and more openly argumentative than a typical reference summary. It is organised in thirteen numbered sections, with twelve figures, a glossary and 26 references. It reviews half a century of entanglement experiments, disputes the standard "no-signal" proofs, designs an experiment that would settle the matter, then follows the consequences if the experiment succeeded: messages received before they are sent, time-loop paradoxes, and an Earth-based operator driving a Mars rover in real time.

It is also candid about the limits. It says there is "at present no compelling answer," suggests that a trade-off between coherence and entanglement may be "nature's way of preventing nonlocal signaling," and ends by saying the question "is an experimental one." There is no mention of UFOs or UAP.

Research Article

The document and the problem it sets

The cover shows the standard DIRD format: "Acquisition Threat Support," 30 March 2010, ICOD 1 December 2009, control number DIA-08-1003-016, one day after D132 (DIA-08-1003-015) in the same numbered block. It was "Prepared by" the Acquisition Support Division (DWO-3), Defense Warning Office, Directorate for Analysis, DIA; the administrative note on page 2 describes it as "one in a series of advanced technology reports produced in FY 2009" and directs comments to AAP Person 1, the AAWSA Program Manager. The AAWSAP Statement of Objectives has no dedicated communications area, so the paper sits best under "supporting topics," with links to "control" (real-time remote operation) and, through its retrocausal scenarios, to "spatial/temporal translation."

The foreword (pages 5-6) sets out the operational problem with numbers. Light needs about 3.3 microseconds per kilometre, "about 1.3 seconds to reach the Moon, between 4.4 and 20 minutes to reach Mars, and between 4 and 4.3 hours to reach Neptune." The result is the need for pre-programmed robots. Special relativity is usually taken to forbid anything faster, but the paper argues that "relativity prohibits only certain forms of superluminal communication." It notes that Einstein, Podolsky and Rosen first highlighted nonlocality in order to object to it, that it has since been demonstrated experimentally, and that only "a few Copenhagen 'holdouts'" still demand a demonstration of signalling before accepting it.

Fifty years of entanglement experiments

Section I explains entanglement through photon polarization: two photons emitted back to back in a zero-angular-momentum state must show the same polarization whenever they are measured in the same basis. The Bell inequalities show that no local "hidden variable" theory can reproduce this pattern of correlations across all bases. The paper then offers its own chronology, saying it wants "to set the record at least somewhat straighter" (page 8). C. S. Wu and I. Shanknov (the document's spelling) measured anticorrelated gamma-ray polarizations in 1949; Freedman and Clauser performed "the first definitive Bell inequality test" in 1972, excluding local hidden variables by 6.7 standard deviations (Figure 1); the Aspect group closed several loopholes in 1982 with 46 standard deviations; and the Gisin group, according to the paper, linked measurements in Geneva and Bern, 156 km apart, over Swiss telephone fibre (page 8).

The paper takes sides on Anthony Leggett's "nonlocal realistic" theories, which the Zeilinger group in Vienna falsified by 3.6 and 9 standard deviations. In its view that test was "mainly an exercise in demolishing a 'strawman,'" and it concludes that "nature is both nonlocal and unrealistic" in the narrow sense Leggett assumed (page 9). It also explains why polarization experiments cannot carry a message: each observer chooses a measurement basis, but "he is not free to force the photon into a particular state of that basis" (page 10).

Questioning the no-signal theorems

Section II is the crux. Standard "no-signal theorems" say that whatever one observer does to their half of an entangled pair, nothing changes in the statistics seen by the other. The paper recasts any signalling test as a test of "parameter independence" and asks whether these proofs "really have the status of mathematical theorems? Perhaps not." It cites an argument that some of them are "tautological," assuming a local measurement process and so building in their conclusion, and concludes that, "at least from some perspectives," nonlocal communication "remains open and appropriate for experimental testing" (page 10). Section III argues that such signals would not violate the Lorentz invariance of special relativity, because their send and receive instants depend on path lengths and cannot synchronize clocks, but admits that causality "appears very likely to be violated" (page 11).

In mainstream physics the no-signalling result is regarded as a consequence of standard quantum mechanics, and no experiment has demonstrated signalling through entanglement. The paper itself acknowledges that no such demonstration existed.

Ghost Interference, Dopfer, and the coherence trade-off

The paper's hope rests on momentum entanglement rather than polarization. Section IV describes the 1995 Ghost Interference experiment of the Shih group (Figures 2-4): 351-nm ultraviolet light from an argon-ion laser, down-converted in a BBO crystal into pairs of 702-nm photons, produced a two-slit interference pattern in the photon that never went near the slits, but only when the two detectors were checked "in coincidence" (pages 12-14). Birgit Dopfer's 1998 Innsbruck thesis experiment (Figure 5) switched an interference pattern on and off by moving a detector in the other arm between two lens positions (page 15). Both needed a classical link to match photon pairs, so neither demonstrated communication. The sources were also poor: only about one pump photon in 10^10 produced an entangled pair (page 13).

Why the coincidence requirement cannot simply be dropped is the subject of Section V. A source of finite size scrambles the phase at the slits and washes out the pattern (the "thick-source effect," Figure 6). Making the source effectively smaller improves coherence but reduces entanglement; the paper cites work at Boston University showing a "complementary relation between source coherence and two-photon entanglement." Signalling needs both, and "where there is coherence without entanglement or entanglement without coherence, nonlocal communication with momentum-entangled photons is not possible." Whether a "sweet spot" with partial amounts of each exists is left open (pages 16-17).

The proposed test and its time budget

Section VI designs the decisive experiment (Figure 7). A lens images one set of slits onto another; optical fibres carry light from the image slits to a switch that sends it either to two separate detectors (giving "which-way" information) or to a combiner (erasing it). A cooled CCD camera on the far arm should then show a single-slit pattern for "1" or a two-slit interference pattern for "0." If it did, that "would falsify the no-signal theorems" (page 19). The paper estimates about 10 photon detections for a 3-sigma decision per bit, calls that "a rather optimistic lower limit," and suggests "perhaps ~100 or more" in practice (page 19). Section VII analyses the set-up with the transactional interpretation of quantum mechanics (Reference 19), in which "offer" and "confirmation" waves form a "two-way handshake" at the crystal (Figures 8-9), and finds "no 'show-stopper' aspects," while stressing that the interpretation "is neutral on whether such signals are possible" (page 22).

Messages from the future, paradoxes and a Mars rover

Sections VIII-X assume, "for the sake of discussion," that the scheme works. Adding two 10-km fibre runs to the sending arm (Figure 10) delays the "send" by about 50 microseconds. With a periodically poled KTP crystal, which the paper says the Vienna group measured at 2.73 x 10^5 pairs per second per mW per nm, a 10 MHz detection rate becomes plausible; with 100 counts per bit, "the message could be received 40 µs before it was sent," a "direct violation of the principle of causality" (page 24). A million such systems would push the gap to 40 seconds, and a "bilking paradox" (receiving a message and deciding not to send it). The paper cites Wheeler and Feynman and Kip Thorne's group for the view that nature enforces consistency, adds an "immaculate conception" paradox in which a novel received from one's future self "has been created out of nothing," and mentions Stephen Hawking's suggestion that nature "abhors" timelike loops (pages 24-25). To avoid all of this, Section X uses equal fibre lengths, so that sending and receiving are separated by a spacelike interval and no loop can form (Figure 11, pages 25-26).

Section XI is the application (Figure 12, pages 26-28). A base station on Mars holds the entangled-photon source; one stream is beamed to Earth, where the operator "sends" by choosing to detect photons as waves or as particles, while the base station reads the other stream locally. Video still arrives with the normal delay, but the control signal, the paper says, would be "sent backwards up the time stream," letting an operator "drive" the rover in real time through virtual reality. Because the loop runs along the light cone, it would cause no paradox.

Nonlinear quantum mechanics and the conclusion

Section XII offers a second route. Steven Weinberg's nonlinear extension of quantum mechanics, Joseph Polchinski showed, would permit an "EPR telephone." Experiments have found no nonlinearity, but the paper suggests it might appear only at very high energy densities or in strong gravity, for example near "a neutron star or black hole," and sketches a curved-space (Laplace-Beltrami) wave equation that becomes nonlinear there (pages 28-29). The half-page conclusion is modest: the matter "is an experimental one," and "at least one experiment in progress aims to produce a coincidence-free version of the Ghost Interference experiment. We await the outcome of such tests" (page 29). The experiment and the group running it are not identified.

Some slips should be noted. The glossary dates the EPR paper to 1936, while the reference list gives 1935; the text dates the Wu-Shanknov measurement to 1949, while its reference gives 1950; Section XII places the no-signal theorems in "Part III" (they are in Section II); and several citations point to the wrong entries (the bilking discussion in the glossary cites References 17-18, which are the Dopfer and Boston University papers).

Significance

D133 is more original and more polemical than the "reference and synthesis" label suggests: it proposes a specific experiment, gives a bit-rate budget and names the physical trade-off most likely to defeat it. For an intelligence program, the attraction was a communication link that would not be delayed by distance, though the paper never discusses military use, adversaries or intercept risk. The mainstream view, that entanglement cannot carry a controllable signal, is unchanged, and the paper's own caveats leave room for exactly that outcome. It has nothing to say about UAP; its connection to the program is the broader AAWSAP interest in physics that might, one day, overturn assumed limits.

Key People

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Key Concepts

Notable Quotes

"The question investigated in this paper is whether quantum nonlocality is the private domain of nature or whether it can be used in experimental situations to send signals from one observer to another. As we will see, there is at present no compelling answer to this question." -- page 6

"It is our view, however, that this is mainly an exercise in demolishing a 'strawman.'" -- page 9

"Do these no-signal 'proofs' really have the status of mathematical theorems? Perhaps not." -- page 10

"It is perhaps likely that the coherence-versus-entanglement tradeoff is nature's way of preventing nonlocal signaling, but that has not been demonstrated." -- page 17

"If 100 photon counts constitute a signal, then, even allowing for the latency in signal reception, the message could be received 40 µs before it was sent." -- page 24

"Yet highly structured information (the novel) has been created out of nothing." -- page 25

"One can imagine driving the Mars Rover around the planet, actively steering around obstacles, activating analysis instruments in real time as interesting objects were found, and actively controlling repair equipment to deal with problems that arise." -- page 27

"Ultimately, the question of whether nonlocal communication is possible is an experimental one." -- page 29