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This Defense Intelligence Reference Document, DIA-08-1004-005, is dated 6 April 2010. The Defense Intelligence Agency's Defense Warning Office prepared it under the Advanced Aerospace Weapon System Applications program. It reviews proposed laboratory generators and detectors for high-frequency gravitational waves. It favors a piezoelectric approach for proof-of-concept tests, IR-excited molecules for an operational transmitter and the Li-Baker detector as the receiver. It estimates about 1.9 million bits per second over 7,000 km through the Earth and discusses timing standards and interplanetary navigation uses.
From the source:Release of 2026-09-18 Incident: 4/6/10, 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 examines whether high-frequency gravitational waves could serve as a communications medium while avoiding the attenuation that limits radio-frequency systems. The report surveys proposed transmitter and detector concepts, argues that gravitational-wave communications could support secure point-to-point links, timing standards, and interplanetary navigation, and gives particular attention to laboratory generator concepts and the Li-Baker detector as possible building blocks for such a system. The document makes clear, however, that the entire concept depends on capabilities that had not been demonstrated in practice, including laboratory-scale generation and reliable detection of usable high-frequency gravitational-wave signals. It is an exploratory systems-oriented review built around a future communications concept.
UNCLASSIFIED//EOR OEEICI0L Llili QI\IL¥ beam is much greater than the stored magnetic field energy, and it follows that E::; ERF = 1011 J to a reasonable approximation. Sources of Quality Factor and Effect on SOL To calculate the SQL, hdet, we also need the value of the detector quality factor Q (not the same as the cavity quality factor). Anything that concentrates or enhances the signal preferentially over noise, in any measurement dimension, can be considered a contributor to the quality factor Q. The quality factor can therefore be understood as the "signal selectivity" in each dimension, so that Qtot = ( Qspatial) (Qt) = QrQsolid angle Qt . (9) The temporal quality factor in the Li-Baker detector arises from averaging the signal over time, so that at 10 GHz, Qt= nt;nt = (10x109 Hz) x 1000s = 1013. There is a contribution to Q arising from the fractal membranes that focus and concentrate the signal photon energy - but not the background photons - along the radial dimension. The radial selectivity arising from the general relativity solution, in conjunction with fractal membranes, is calculated by Li et al. (2008). Their table III gives Qr= SNRrr=J7cmJ/SNRrr=J.scmJ = 3.4x1021 . This is mostly due to the effective Q contribution arising from the synchro-resonance solution to the Einstein field equations that limit the PPF signal to a radiation pattern in certain directions, whereas noise is distributed uniformly. By utilizing directional antennas, the Li-Baker detector can capitalize upon this gain due to the focusing power of fractal membranes as a contribution to Q in angular space as well. This is calculated in detail, octant by octant, by Li et al. (2008). Page 24 of Li et al. summarizes this in terms of angular concentration onto the detector. A non-directional antenna corresponds roughly to solid angle 21r steradians (one hemisphere), so that the effective antenna gain is estimated as (Qsolidangle) = 2n sr/10-4sr = 6.3x104 . Therefore, the predicted maximum quality factor will be Qtotal = QrQsolidang1eQt = 2.1 x1039 . This finally gives the Standard Quantum Limit (SQL) for stochastic GW detection at 10 GHz: hdet = (1/Q) 112cncv/E) 112 = 1.Sxl0-37 m/m . (10) Comparison of SOL With Predicted Sensitivity As noted in the previous section, hdet = 1.Sxl0-37 m/m represents the lowest possible GW amplitude detectable by each RF receiver in the Li-Baker HFGW detector, limited by quantum back-action. An additional (1/ ✓ 2) factor applies if the separate outputs from the two RF receivers are averaged, rather than used independently for false alarm reduction, resulting in a minimum hdet = 1.2x10-37 . Since the predicted best sensitivity of the Li-Baker detector in its currently proposed configuration is A = 10-32 m/m, these results confirm that the Li-Baker Detector is photon-signal limited, not quantum noise limited; that is, the Standard Quantum Limit is so low that a properly designed Li-Baker detector can have sufficient sensitivity to observe HFRGW of amplitude A ~ 10-32 m/m. UNCLASSIFIED/ /FOR OEEICIJ.b HSI!! Dflti 19
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 57 pages are in the text index: search them above, or from the library's search.