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

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CASIMIR EFFECT REVISITED
The most-quoted quintessential configuration for the conversion of vacuum energy to
other forms of energy is the Casimir effect. As previously discussed, when parallel
conducting plates are placed in a vacuum, they attract one another by a very weak
force that varies inversely as the fourth power of the distance between them. First
computed by Casimir in terms of van der Waals forces (a matter-fields approach - see
below), he soon realized that, because the force turns out to be independent of the
molecular details of the conductors, it could be computed as a problem in vacuum
energy, and that is the way it is now generally presented in the literature (the "plenum
approach") (Reference 5, 62).
Casimir Effect in the Plenum Picture
One begins with the free quantum vacuum electromagnetic field fluctuations, and then
determines their modification due to the insertion of two parallel plane conductors (that
is, plates) as additional boundary conditions, which constrain a discrete set of intra-
cavity modes of integer half-wavelengths. Aside from an unobservable, high-frequency-
cutoff-dependent, free-field term that remains from the mathematical regularization
procedure, the resulting (renormalized) vacuum stress-energy tensor9 is given by
(r..i.~·) =(rr'hc / 720d., )diag( -1, I, I, -3), where the angular brackets denote the quantum
(vacuum state) expectation value of the tensor T,'.::·, d is the plate separation, and
diag(-1,1,1,-3) denotes the diagonal elements of a 4x4 matrix (Reference 1-3, 62). 10
(1~1.::·) represents the real physical stress carried by the vacuum field fluctuations in the
presence of the parallel plane conductors, and it encodes the Casimir effect in terms of
(1) an interaction energy per unit area, EI A= -rr'hc/720d', and (2) a corresponding
force per unit area, FI A= -rr'hc 1240d". If free to move in response to the attractive
Casimir force, the motion of the plates toward each other is understood in the plenum
approach to progressively eliminate intra-cavity modes, converting their associated
ground-state energies first into kinetic energy, and then, upon collision of the plates,
into heat. Section II described the Casimir-force-driven collapse of Forward's charged
slinky as a Casimir-type configuration for building up an electric field to charge a
battery, and how such processes were shown not to violate either conservation of
energy or thermodynamic constraints.
Casimir Effect in the Fluctuating Matter Fields Picture
Complementary to the vacuum mode description (plenum approach), the Casimir effect
can be described, like van der Waals attraction, as arising from correlations in the state
of electrons in the two plates through the intermediary of their coupled fields. From this
standpoint (matter-fields approach) there is no requirement for the high energy density
vacuum field of the plenum approach to reside throughout all space.
9 The stress·energy-momentum tensor, Tc"', is a matrix quantity that encodes the density and flux of a matter
source's energy and momentum. Greek indices denote the matrix components over the spacetime coordinates.
'"For this derivation, the vacuum fluctuations of other quantum fields are essentially undisturbed by the presence
of the conductors or are affected only in the immediate vicinity of the atomic nuclei that they contain.
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