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This Defense Intelligence Reference Document from the Defense Intelligence Agency, dated 6 April 2010, is one in a series of FY 2009 advanced technology reports produced under the Advanced Aerospace Weapon System Applications (AAWSA) program. It reviews the physics of zero-point field energy in the quantum vacuum and proposed schemes for extracting it, including the Casimir effect, Forward's vacuum-fluctuation battery, and resonant dielectric spheres. It notes that no practicable extraction technique has been demonstrated in the laboratory.
UNCLASSIFIED//F811. 8FFll!l*L 1!1!11! t!IIU:!Y might work, it is necessary to characterize the physics of the ZPF and proposed energy extraction techniques, and to evaluate their feasibility for application to space power and propulsion systems. In what follows, the physics of the ZPF and the experimental investigations being pursued to address the question of extracting energy from the quantum vacuum are summarized. III. Origin of Zero-Point Field Energy ELEMENTS OF QED THEORY The basis of the ZPF is typically attributed to the Heisenberg Uncertainty Principle. According to this principle, A and B are any two conjugate observables that one is interested in measuring, and they obey the commutation relation [A,B] = in. 4 Their corresponding uncertainty relation is ML',.8 :c:. fl/2, where Mis the variance (aka uncertainty) of observable A and L',.8 is that of the conjugate observable B. This relation states that if one measures observable A with very high precision (that is, its uncertainty M is very small), then a simultaneous measurement of observable B will be less precise (that is, its uncertainty L',.8 is very large), and vice versa. In other words, it is not possible to simultaneously measure two conjugate observable quantities with infinite precision. This minimum uncertainty is not due to any correctable flaws in measurement, but rather reflects the intrinsic fuzziness in the quantum nature of energy and matter. Substantial theoretical and experimental work has shown that in many quantum systems the limits to measurement precision is imposed by the quantum vacuum ZPF embodied within the uncertainty principle. Nowadays one would rather see the Heisenberg Uncertainty Principle as a necessary consequence, and therefore, a derived result of the wave nature of quantum phenomena. The uncertainties are just a consequence of the Fourier nature of conjugate pairs of quantities (observables). For example, the two Fourier-wave-conjugates time and frequency become the pair of quantum-particle conjugates time and energy and the two Fourier-wave-conjugates displacement and wavenumber become the pair of quantum-particle conjugates position and momentum. For more on this see, for example, Reference 13. Classically, electromagnetic radiation can be pictured as waves flowing through space at the speed of light. The waves are not waves of anything substantive, but are in fact ripples in the state of a field. These waves carry energy, and each wave has a specific direction, frequency and polarization state. This is called a "propagating mode of the electromagnetic field." A useful tool for modeling the propagating mode of the electromagnetic field in quantum mechanics is the ideal quantum mechanical harmonic oscillator: a hypothetical charged mass on a perfect spring oscillating back and forth under the action of the spring's restoring force. The Heisenberg Uncertainty Principle dictates that a quantized harmonic oscillator (aka a photon state) can never come entirely to rest, since that would be a state of exactly zero energy, which is forbidden by the commutation relation outlined above. Instead, every mode of the field has flw/2 as its average minimum energy in the vacuum. 5 (This is a small amount of energy, but the number of modes is enormous, and indeed increases as the square of the frequency. The product of this minuscule energy per mode, multiplied by the huge spatial density of modes, yields a very high theoretical energy density per unit volume.) 1 1 1s the unit complex number. fl is Planck's reduced constant, 1.055 x 10 31 J-s. 5 w is the mode or photon frequency and flw is the energy of a single mode or photon. 4 UNCLASSIFIED//FOll OFFlfalPk llili O•lk¥
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Report, from the dia 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.