Defense Intelligence Reference Document Concepts For Extracting Energy From The Quantum Vacuum

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of ideal or real metals at a temperature of absolute zero. Non-zero temperature
corrections for flat, real metals are uncertain. There are fundamental disagreements
about the computation of vacuum forces for spheres or rectangular cavities, and
about how to handle real material properties and curvature in these and other
geometries. Indeed, it is very difficult to calculate Casimir forces for these simple
geometries and to relate the calculations to an experiment. Calculations have yet to
be done for more complex geometries. The usual problems in QED (for example,
divergences due to unrealistic boundary conditions, to curvature, to interfaces with
different dielectric coefficients) abound. These problems require theoretical and
experimental resolution.
• As stated in Section V, there is need to find new boundary conditions for the
vacuum that can alter the vacuum energy density by orders of magnitude more than
with the current boundary conditions, which are primarily metallic or dielectric
surfaces. Perhaps the use of new materials (for example, those with a negative
index of refraction, or an ultra-high electrical carrier density, either steady state or
transient), or novel condensed matter (superconducting) materials may open the
door to new Casimir phenomena. Recently the use of (negative index)
metamaterials was proposed to make a repulsive Casimir force (Reference 113).
With significantly increased funding for research, some breakthroughs in this area
might be possible.
• There are several important experiments that can aid our understanding of vacuum
energy and Casimir forces that may lead to significant improvements in our
engineering capability:
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Experiments measuring the Casimir forces for semiconductor surfaces would be
helpful in the development of new applications of vacuum forces and to
demonstrate that it is possible to alter the Casimir force by altering the carrier
density.
- The measurement of Casimir forces and energies for different geometry and
composition objects, such as rectangular cavities or spheres, would provide data
for theoretical modeling. Measurements of Casimir forces between separate,
nonplanar surfaces are also needed. There may be surfaces that have larger
forces than the classic parallel plates.
- New boundary conditions or new methods of modifying the known quantum
vacuum boundary conditions may be needed to generate the large changes in
free-field vacuum energy required if "vacuum engineering" as proposed in this
report is ever to become practical. For example, the vacuum energy density
difference between parallel plates and the region outside them in free space is
simply not large enough in magnitude for large-scale engineering purposes.
Energy densities, positive or negative, that are orders of magnitude greater are
required. Such energy density regions may be possible, at least in some cases.
For example, a region appeared in the one-dimensional dynamic system in which
the energy density was below that of the Casimir parallel plate region (Reference
114).
- Experiments to verify the adiabatic Casimir effect have been suggested in the
literature. This is an important theoretical issue that has ramifications in different
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