Documents / Report
This Defense Intelligence Reference Document from the Defense Intelligence Agency is dated 2 April 2010 and was produced under the Advanced Aerospace Weapon System Applications (AAWSA) Program. It is one of a series of advanced technology reports from FY 2009. It reviews general relativistic warp drives, the cosmological constant, Casimir energy and extra space dimensions. It proposes that dark energy may come from higher dimensions and that controlling those dimensions could one day make a warp drive possible.
UNCLASSIFIED/ ;ran 8FFlil11ds WOli 8PJLY strong nuclear forces could also be described using QFT. The full theory, called the Standard Model of particle physics, is arguably the most successful physical theory to date. Despite the successes of the Standard Model, incorporating gravitational interactions using the methods of QFT has proven to be one of the most challenging problems facing theoretical physics today. String theory is currently the best candidate for a quantum theory of gravity (Reference 29). The divergences associated with point particle gravitational interactions are removed in string theory via the extended nature of the string. A review of string theory falls far outside the scope of this paper; however, the theory contains numerous compelling features that deserve mention here. One of the most discussed aspects of string theory is its prediction that additional dimensions of space exist, and are indeed required for string theory to work. One of the predictions of string theory is that these additional dimensions are extremely small, on the order of 10-35 m. However, there are also popular models which attempt to explain certain aspects of nature that involve large extra dimensions which we will briefly introduce. 5.2 LARGE EXTRA DIMENSIONS Models with large extra dimensions have enjoyed a revived interest in physics. This began with the Arkani-Hamed, Dimopoulos, and Dvali (ADD) proposal to lower the quantum gravity scale to the 10 to 100 TeV scale 10 (accessible to the next generation of particle accelerators) by embedding the Standard Model fields in a 3+1 dimensional brane existing in a higher dimensional bulk spacetime (Reference 30, 31). Gravity is free to propagate in the bulk, which effectively dilutes its strength. This idea was inspired by M-theory, where it was recognized that the scale of quantum gravity could be lowered from the Planck energy scale to the Grand Unification Theory (GUT) energy scale (Reference 32-35). 11 The assumptions underlying the ADD model are: • n-extra dimensions compactified on a torus with volume v" = (2nr)'1. • Standard Model fields are localized to the brane. • Gravity can propagate in the bulk. • There is no cosmological constant in the bulk or on the boundary. • The brane is stiff. The bulk action for this model can be given by: S ~- I i1t • where g is the matrix determinant of the metric and the two tilde-quantities are the 4+n dimensional Planck mass and Ricci scalar, respectively. By integrating out the extra dimensions, it is simple to show that: 10 1 TeV = 10 12 eV (1 eV = 1.602 x 10-19 J) is a mass-energy scale used in elementary particle physics. "Planck energy (ric5/GJ 1i 7 "' 1078 eV; GUT energy> 10'4 GeV (1 GeV = 109 eV). 10 UNCLASSIFIED//f'8ft 8PFl@IAL W&i 8Plb¥ (5.2)
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 33 pages are in the text index: search them above, or from the library's search.