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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.
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UNCLASSIFIED//FIHl 8FFHil.t.L '11815 8HL?/ Appendix: The QCD Bag Model When considering the effective masses of quarks bound within hadrons, it is common to think of the constituent masses of the quark and antiquark pair as their zero-point energy (ZPE) when they are bound by the confining potential 25 (acting between a quark and an antiquark) with an energy spectrum that corresponds to the masses of the observed mesons. For charm, and heavier quarks, it appears that the total ZPE is not much different from the masses of the lowest-lying meson states. This picture also holds true for baryons. The quark-gluon model for hadrons is called "the bag model." Even in an "empty" bag-that is, one containing no quarks-there will be nonzero fields present because of quantum zero-point fluctuations (ZPF). This gives rise to a zero- point (ZP) or Casimir energy inside the empty bag. The estimated total ZP/Casimir energy of the confined gluon field inside a spherical bag is EzP""' +0.7/a (or +0.7flc/a in MKS units), where a is the radius of the bag in GeV- 1 units. EzP is numerically the entire story because the ZPE contribution of the confined fermion (quark) field is far smaller than EzP (the leading approximation per degree of freedom is down by two orders of magnitude). A typical empty bag has an estimated radius a"" 2.6 Gev-1 (0.5 fm), so EzP ~ 10-1 GeV (or 10-11 J), and this result remains approximately true if one uses a= 5.07 Gev- 1 (1 fm) for a nucleon-sized bag. If the bag contains quarks, then this result does not change because the quarks don't affect the ongoing quantum ZPF inside the bag due to asymptotic freedom. The inventor of the empty bag model (Ken Johnson) proposed that space is filled with closely packed empty bags, and that the energy of space filled with contiguous bags is simply the sum of the field energies contained within each bag. But this is not widely accepted since the phenomenologically preferred model for the exterior "ordinary" vacuum is given as follows. QCD color confinement in hadrons is approximated by the phenomenologically successful "bag model." In this model, the "ordinary" vacuum external to hadrons is a perfect color magnetic (or chromomagnetic) conductor; that is, the chromomagnetic permeabilityμ is infinite, while the chromomagnetic vacuum in the interior of the bag is characterized byμ= 1. This implies that the color electric (EQco) and magnetic (BQco) fields are confined to the interior of the bag, and that they satisfy the following boundary conditions on its surface S: n • EQco Is= 0, n x BQco Is= 0, where n is a unit normal vector to S. In other words, this model defines QCD vacua that coexist in two phases: 1) an ordinary vacuum exterior to the bag, impenetrable to color; and 2) a vacuum interior of the bag, in which the Yang-Mills fields that carry color (gluons) propagate freely. Both phases are separated by the surface boundary of the bag upon which the Yang-Mills and fermion (quark) field satisfy the aforementioned boundary 25 Quarks carry "color charge" as well as electric charge. Color charge is considered to be the "true" charge of strong interactions. Gluons are the "photons" of strong interactions, and color is exchanged by eight bicolored gluons, which are massless and have spin 1. Color interactions are assumed to be a copy of electromagnetic interactions. Theoretical and phenomenological studies found that the confining potential V(r) lies between a Coulomb and a harmonic oscillator potential: V(r) = -(4a, J 3r) + kr, where r is the radial distance between confined quarks, k is a constant parameter, and f is the color factor associated with as for the case of quark- antiquark pair confinement in mesons. For the case of baryons (qqq), the color factor in V(r) is replaced by ~. 42 UNCLASSIFIED/ /FIUl 8FFIIIAL 1!1815 &••tY
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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.