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AAWSAP DIRD, Quantum Tomography of Negative Energy States in the Vacuum, January 2011

U.S. Department of War · 2011-01-11 · 51 pages · text from the file's own layer

This Defense Intelligence Reference Document, dated 11 January 2011, was prepared by the Defense Intelligence Agency's Defense Warning Office under the Advanced Aerospace Weapons System Applications program. It reviews negative, or sub-vacuum, energy found in the Casimir effect and squeezed light, and describes quantum optical homodyne tomography for measuring it. It proposes balanced homodyne detector systems to map negative energy. It also suggests that arrays of such sensors could detect anomalous aerospace platforms that use engineered spacetime effects for propulsion.

From the source:Release of 2026-09-18 Incident: 1/11/11, 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 how negative-energy, or “sub-vacuum,” states in quantum fields might be detected and mapped. Its practical scope is limited to the laboratory-scale measurement of minute quantum effects, though it extrapolates from those effects to consider theoretical relevance to concepts such as warp drives, wormholes, or gravitational control. By reviewing previously identified laboratory examples such as the Casimir effect and squeezed light states, the report identifies the core technical challenge as mapping their spatial and temporal structures reliably. To address this, it proposes quantum optical homodyne tomography as a method to reconstruct and quantify the vacuum fluctuations associated with these states. The document acknowledges that only microscopic, transient negative-energy effects have been realized in laboratory settings. It remains unknown whether larger or longer-lived distributions of such effects can be generated or stabilized, particularly given the experimentally unresolved constraints imposed by quantum inequalities. Overall, this DIRD functions as a measurement- and diagnostics-oriented review intended to lay experimental groundwork for a far more ambitious, highly speculative negative-energy research agenda.

  • p. 5 …A first step in this direction was already taken by Hansen et al. 4 in 2001…
  • p. 38 …Time-domain BHD resolves th is limitation. Hansen et al. 4 describe their experimental time-domain…
  • p. 39 …mode that matches that of the LO. Hansen et al. 4 point out that time-domain…
  • p. 47 …Nearly a decade ago, Hansen et al. 4 reported on their experimental time-domain (or pulsed…
  • p. 50 …1016-1022. 4 Hansen, H., et al. (2001), "Ultrasensitive pulsed, balanced homodyne detector: application to time…
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drawback of this approach is that it reveals information about the quantum state only
within the sideband chosen for the measurement. Therefore, the method is
incompatible with other techniques for characterizing a quantum state for which such
precise selection of spectral modes is impossible. Time-domain BHD resolves th is
limitation. Hansen et al. [4] describe their experimental time-domain BHD device.
They developed a pulsed BHD for precise measurement of the electric field quadratures
of pulsed optical quantum states. A high level of common mode suppression(> 85 dB)
and low electronic noise (730 electrons per pulse) in their device provides a signal-to
noise ratio of 14 dB for measurement of the quantum noise of individual pulses. Their
device achieved a signal-to-noise ratio of 14 dB at a pulse repetition rate of up to 1 MHz,
enabling high-accuracy quantum measurements to be carried out in a short time. They
performed a quantum tomography of the coherent state as a test for their device, and
the Wigner function and density matrix were reconstructed with 99.5% fidelity while
their detector exhibited 91 % quantum efficiency. Their detection system can also be
used for ultrasensitive balanced detection in continuous wave mode. Figure 13 shows a
schematic of their time-domain BHD. The figure shows two polarizing beam splitter
(PBS) cubes, a 50:50 beam splitter (BS), two half-wave plates (A/2), two photodiodes
(left-side in dotted box), and the signal processing electronics inside the dotted box.
;-·-- -·- --·------·--- ·-- -·---·--- ·-- -· --- ·------ ··I
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lo~ pass
ilter
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Figure 13. Time-Domain Balanced Homodyne Detector. (courtesy of P. Lodahl)
As we discussed previously in Sections IIIB-4 and IIIB-5, to perform BHD one overlaps
on a beam splitter the electromagnetic wave whose quantum state is to be measured
and a relatively strong LO wave in the matching optical mode. The two fields emerg in g
from the beam splitter are incident upon two high efficiency photodiodes whose output
photocurrents are subtracted. The photocurrent difference is proportional to the value
of the electric field operator E in the signal mode, where 8 is the relative optica l0
phase of the signal and the LO. In traditional frequency-domain BHD, one uses a
certain frequency component of the difference signal to determine the quadrature
quantum noise of the optical state. The measurement frequency is normally chosen to
be approximately 5 to 10 MHz where the technical noise is minimized. Figure 14 shows
an example of experimentally measured data for a typical (undisturbed) vacuum state
and a squeezed vacuum state using a time-domain BHD system.
UNCLASSIFIED// FOR OFFICIAL U.!r:: er•t'
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 51 pages are in the text index: search them above, or from the library's search.