DIA, 2010: dois estudos do AAWSAP discutem, em teoria, a “dobra espacial” e buracos de minhoca para viajar mais rápido que a luz

Warp Drive, Dark Energy, and the Manipulation of Extra Dimensions. Prepared by: Acquisition Support Division (DWO-3) Defense Warning Office Directorate for Analysis Defense Intelligence Agency. Authors: [AAP Person 74], [AAP Person 58]. Administrative Note. COPYRIGHT WARNING: Further dissemination of the photographs in this publication is not authorized. This product is one in a series of advanced technology reports produced in FY 2009 under the Defense Intelligence Agency, Defense Warning Office's Advanced Aerospace Weapon System Applications (AAWSA) Program. Comments or questions pertaining to this document should be addressed to [AAP Person 1], AAWSA Program Manager, Defense Intelligence Agency, ATTN: CLAR/DWO-3, Bldg 6000, Washington, DC 20340-5100.

Warp Drive, Dark Energy, and the Manipulation of Extra Dimensions. Introduction. If one is to realistically entertain the notion of interstellar exploration in timeframes of a human lifespan, a dramatic shift in the traditional approach to spacecraft propulsion is necessary. It has been known and well tested since the time of Einstein that all matter is restricted to motion at sublight velocities (<< 3 x 10^8 m/s, the speed of light, or c), and that as matter approaches the speed of light, its mass asymptotically approaches infinity. This mass increase ensures that an infinite amount of energy would be necessary to travel at the speed of light, and, thus, this speed is impossible to reach and represents an absolute speed limit to all matter traveling through spacetime. Even if an engine were designed that could propel a spacecraft to an appreciable fraction of light speed, travel to even the closest stars would take many decades in the frame of reference of an observer on Earth. Although these lengthy transit times would not make interstellar exploration impossible, they would certainly dampen the enthusiasm of governments or private individuals funding these missions. After all, a mission whose success is perhaps a century away would be difficult to justify. In recent years, however, physicists have discovered two loopholes to Einstein's ultimate speed limit: the Einstein-Rosen bridge (commonly referred to as a “wormhole”) and the warp drive. Fundamentally, both ideas involve manipulation of spacetime itself in some exotic way that allows for faster-than-light (FTL) travel. Essentially, the wormhole involves connecting two potentially distant regions of space by a topological shortcut. Theoretically, one would enter the wormhole and instantaneously be transported to the exit located in a distant region of space. Although no observational evidence of wormholes exists, theoretically they can exist as a valid solution to general relativity. The warp drive—the main focus this paper—involves local manipulation of the fabric of space in the immediate vicinity of a spacecraft. The basic idea is to create an asymmetric bubble of space that is contracting in front of the spacecraft while expanding behind it. Using this form of locomotion, the spacecraft remains stationary inside this “warp bubble,” and the movement of space itself facilitates the relative motion of the spacecraft. The most attractive feature of the warp drive is that the theory of relativity places no known restrictions on the motion of space itself, thus allowing for a convenient circumvention of the speed of light barrier. An advanced aerospace platform incorporating warp drive technology would profoundly alter the capacity to explore—and potentially to colonize—the universe. Because a warp drive is not limited by the speed of light, one can only guess the top speeds such a technology might be capable of achieving. For the sake of argument, let's consider the duration of trips taken by a [p. 6] spacecraft capable of 100c(1) for an array of exotic destinations of possible interest. As Table 1 shows, trips to the planets within our own solar system would take hours rather than years, and journeys to local star system would be measured in weeks rather than hundreds of thousands of years. Table 1. Transit Times to Various Exotic Destinations at 100 Times the Speed of Light: Mars 193 seconds; Jupiter 36 minutes; Neptune 4 hours; Alpha Centauri 15 days; Epsilon Eridani 38 days; The Orion Nebula 1.3 years. Until recently, the warp drive was a concept reserved for science fiction. However, a 1994 paper by Miguel Alcubierre placed the idea on a more solid theoretical footing. Alcubierre (Reference 1) demonstrated that a specific Lorentzian manifold could be chosen that exhibited bubble-like features reminiscent of the warp drive from the popular Star Trek television series. The bubble allowed for the surrounding spacetime to move at FTL speeds, and the inhabitants of the bubble would feel no acceleration effects because spacetime itself would be in motion instead of the spacecraft and its inhabitants. A number of papers have emerged in recent years that build on this original idea. However, these papers do not typically address how one might actually create the necessary spacetime bubble. Our own research directly addresses this question from a new and unique perspective and introduces a novel paradigm shift in the field of warp drive study (Reference 2). More formally, our work approaches the physics of warp drive from the perspective of quantum field theory; this diverges from the more traditional approach to warp drives, which utilizes the physics of general relativity. One of the improvements the model introduces is a dramatic reduction in the overall energy required to create such a phenomenon. The roadmap to this new idea was the observation that spacetime is currently known to be in a state of accelerated expansion, as demonstrated by the redshifting of galaxies, and the belief that if the mechanism for this expansion could be understood, then it might ultimately be controlled. A popular term used by cosmologists today is “dark energy,” an exotic and ubiquitous form of energy that is believed to constitute over 70 percent of the matter-energy content of the universe (Reference 3-6). One salient feature of dark energy is its intrinsic ability to generate negative pressure, causing the fabric of space to expand in the way that is currently observed (Reference 7). [footnote 1: This speed, while somewhat arbitrary, highlights the fact that our galaxy would become far more accessible if or when one discovers how to surpass the speed of light barrier.] [p. 7] Although we know what dark energy does, we do not yet fully understand its nature. We do not understand why it exists or how it is created; we simply know it provides an ever-present force on spacetime, causing the universe to expand. Indeed, recent high-precision experimental observations indicate dark energy may be a cosmological vacuum energy (Reference 8-10). These observations are based on the magnitudes of high-redshift supernova and have been a source of high research activity of late owing to the unexpected discovery that the rate of expansion of the universe is increasing (commonly referred to as accelerated expansion). One tantalizing aspect of dark energy is that if it were fully understood, and if a technology were developed that could generate and harness the exotic effects of dark energy on the fabric of space, then a warp drive would be one step closer to technological reality. While a full understanding of the true nature of dark energy may be many years away, it is entirely feasible that experimental breakthroughs at the Large Hadron Collider or developments in the field of M-theory could lead to a quantum leap in our understanding of this unusual form of energy and perhaps help to direct technological innovations. Our own research focuses on gaining an understanding of the physical origin of dark energy. By exploring novel ideas at the forefront of theoretical physics, one is able to propose a physically viable model incorporating some of the cutting-edge ideas emerging from string theory and quantum field theory. This leads to a deeper understanding of the possible origin of dark energy and allows consideration of a mechanism that would allow a sufficiently advanced technology to control the dark energy density in any region of space, and thus the expansion of space. This work has clear implications for the advancement of warp drive research. This paper is structured as follows: Section 2 reviews the more traditional general relativistic warp drives, the energy required to create them, and the physics required to understand them. Section 3 discusses the cosmological constant, a term featured in Einstein's equation that regulates the contraction and expansion of the spacetime. Section 4 introduces the Casimir energy, which, under certain conditions, may be the phenomenon that physically generates the cosmological constant. Section 5 discusses higher dimensions in physics and their importance in the context of Casimir energy calculations. Section 6 introduces the formulas that demonstrate that the Casimir energies in higher dimensions may in fact be the dark energy that is responsible for the accelerated expansion of the universe. Section 7 relates all the previous concepts together and introduces the novel warp drive paradigm. Section 8 performs original calculations of the energy required to create a superluminal warp drive. Finally, the paper speculates about the technological progress that would be necessary to turn this model into a reality.

[...] understanding and experimentation with warp drive technology. To understand how, first discuss an analogy with energy w > 1. In a handful of labs scattered around the country, petawatt lasers are being built and tested. These are lasers of profound capability, able to generate short laser pulses of intensity >> 10^15 W/m^2 with peak focused power densities of >> 10^27 W/m^3 and energy densities of >> 10^16 J/m^3. If it were possible to construct an exotic device whose energy output had w < 1, then using calculations identical to those to generate Table 3, it would seem straightforward to show that the energy density produced by an analogous dark energy laser would translate into a local expansion of space corresponding to V warp = 10^-13 or ~ 10^-5 m/s for every meter of space that the laser travels. It may be possible to construct an experiment that could measure the modified expansion of space along the length of such a laser to test the predictions of this paper. 7.6 THE DEVELOPMENT OF THE TECHNOLOGY. Although a practical warp drive could be many years away from realization, there are a number of technological developments that may, in fact, be necessary in order to allow prototype experiments to begin. First, a more complete understanding of dark energy is of paramount importance. As mentioned earlier, dark energy contributes approximately 70 percent of the overall energy density of the universe, and is responsible for the expansion of space. As one acquires deeper understanding of this energy, attempts to generate dark energy in the lab would no doubt be a critical component to a working warp drive. Other crucial developments include determining whether extra dimension are, in fact, real. Once this has been determined with absolute certainty, the role of extra dimensions and their relationship with the universe that we are more familiar with will become a more serious focus of scientific research and attention. As has been discussed, the stabilization of the extra dimensions and the accelerated expansion of the remaining four dimensions can be realized via the Casimir energy. The acceleration of the 3-dimensional subspace is a naturally occurring phenomenon which occurs when the extra dimensions are stabilized. An important feature of the higher dimensional model is the dependence of the dark energy density on the size of the extra dimensions. In models with large extra dimensions, the interaction of the graviton KK tower with the Standard Model fields are suppressed by the higher dimensional Planck scale and the corresponding couplings are inverse TeV in strength. This can be seen more clearly when we consider the expansion of the metric tensor in models with large extra dimensions computed within linearized gravity models: [equation 7.7] where the capital letter indices indicate summation over the higher dimensions, M is the modified Planck mass, η MN corresponds to flat (Minkowski) spacetime and h MN corresponds to the bulk graviton fluctuations. The graviton interaction term in the action is expressed by:

[equation 7.8] where T MN is the higher dimensional energy-momentum tensor. The interaction of the graviton with the graviton KK states and with the SM fields are obtained by integrating the action over the extra coordinates. Because all these states are coupled with the universal strength 1/M Pl this leads to the compelling possibility of the control of the size of the extra dimensions by processes at energies that will be accessible via the particle accelerators of the near future. Although the coupling is extremely small, the effective coupling is enhanced by the large number of KK states. Referring to Figure 7, additional energy in the form of matter or radiation with the TeV energy scale can alter the shape of the effective potential. In particular, the extrema determining the size of the extra dimensions are modified with the change of the Casimir energy density and hence, the dark energy density, in the models under consideration. In the ADD model discussed in Section 5.2, the Standard Model fields are confined to a 4-dimensional brane and a new gravity scale M D >> TeV is introduced in the D = 4 + d dimensions, where d is the number of extra dimensions. This is determined quite easily by forming the higher dimensional action and integrating out the extra dimension. The Atlas experiment at CERN's Large Hadron Collider will have the capability to probe the ADD type extra dimensions up to M D ~ 8 TeV. In the Randall Sundrum scenario, the hierarchy is explained by the warp factor in the AdS5 bulk geometry. A lower bound can be placed on the lowest KK mass by electroweak precision tests (masses on the order of 1 TeV are allowed). In the Universal Extra Dimension scenario, Tevatron results constrain the compactification scale to Mc > 400 GeV. Because the Atlas experiment will be sensitive to Mc ~ 3 TeV, the estimates in this section indicate that if nature is in fact described by one of these higher dimensional scenarios, then the additional dimensions can be probed. Even more exciting is the possibility that their size may be controlled at the energies accessible to the Large Hadron Collider. When the Casimir energy to play the role of dark energy is involved, one can see that the possibility for the direct control of the local dark energy density by controlling the size of the additional dimensions is possible. 8. Summary. The idea that a sufficiently advanced technology may interact with, and acquire direct control over, the higher dimensions is a tantalizing possibility, and one that is most certainly worthy of deeper investigation. Control of this higher dimensional space may be a source of technological control over the dark energy density and could ultimately play a role in the development of exotic propulsion technologies; specifically, a warp drive. Of course, this may not be actualized until many years in the future, but consider the many spectacular physical phenomena that are believed to be true at this early point in [p. 32] the 21st century. One believes that an energy field called the Higgs boson permeates spacetime and that the interaction of matter with this field is what is responsible for particles acquiring mass. One believes that an exotic ubiquitous energy source, unimaginatively named dark energy, is responsible for the current accelerated expansion of the universe based on observation of supernova in galaxies billions of light years from Earth. One also believes that the universe may not consist of the three spatial dimension of length, breadth, width, and one of time, but that, in fact, there may be as many as seven additional compactified dimensions assuming the topology of a Calabi-Yau manifold, and that the fundamental building blocks of the universe are, in fact, extended string-like entities. Modern physics is full of many exciting and marvelously imaginative creations. Because one understands these curiosities, one could potentially harness these elements of nature for one's own technological ends. This is by no means a certainty, but if we may make predictions based on the innovative history of scientific pioneers of the past, then it seems entirely possible that the creative minds of the future may indeed find ways to accomplish what, to us, may seem like magic.

Traversable Wormholes, Stargates, and Negative Energy. Prepared by: Acquisition Support Division (DWO-3) Defense Warning Office Directorate for Analysis Defense Intelligence Agency. [AAP Person 58]. Administrative Note. COPYRIGHT WARNING: Further dissemination of the photographs in this publication is not authorized. This product is one in a series of advanced technology reports produced in FY 2009 under the Defense Intelligence Agency, Defense Warning Office's Advanced Aerospace Weapon System Applications (AAWSA) Program. Comments or questions pertaining to this document should be addressed to [AAP Person 1], AAWSA Program Manager, Defense Intelligence Agency, ATTN: CLAR/DWO-3, Bldg 6000, Washington, DC 20340-5100.

Traversable Wormholes, Stargates, and Negative Energy. I. Summary. Implementation of faster-than-light (FTL) interstellar travel via traversable wormholes generally requires the engineering of spacetime into very specialized local geometries. The analysis of these via Einstein's General Theory of Relativity, plus the resultant equations of state, demonstrates that such geometries require the use of “exotic” matter. It has been claimed that since such matter violates the energy conditions, FTL spacetimes are not plausible. However, it has been shown that this is a spurious issue. The identification, magnitude, and production of exotic matter are seen to be a key technical challenge, however. These issues are reviewed and summarized, and an assessment on the present state of their resolution is provided. In 1985 CalTech physicists M. Morris and K. Thorne discovered the principle of traversable wormholes based on Einstein's General Theory of Relativity (published in 1915). Morris and Thorne (Reference 1) and Morris et al. (Reference 2) did this as an academic exercise at the request of Carl Sagan, who had completed the draft of his novel Contact. This little exercise led to the development of two new cottage industries in spacetime physics research: the study of traversable wormholes and the study of time machines. Wormholes are hyperspace tunnels through spacetime connecting either remote regions within our universe or two different universes; they even connect different dimensions and different times. Space travelers would enter one side of the tunnel and exit the other, passing through the throat along the way. The travelers would move at ≤ c (c is the speed of light, 3 x 10^8 m/s) through the wormhole and therefore not violate Special Relativity, but external observers would view the travelers as traversing multi-light-year distances through space at FTL speed; Figure 1 illustrates this effect. A “stargate” is a special class of traversable wormhole solutions to Einstein's general relativistic field equation that possesses very simple physics and flat entry and exit openings. Traversable wormholes are unlike the well-known, non-traversable Einstein-Rosen Bridges or Schwarzschild wormholes that are formed from collapsed stellar matter (that is, black holes) or spherically symmetric vacuum regions. Black holes are collapsed stars that have all their mass concentrated at an infinitesimal point where the induced gravitational field crushes all matter and spacetime. However, even Einstein-Rosen bridges can be made traversable by an infinitesimal tweaking of their spacetime metric. In the case of black holes, the singularity of collapsed matter, along with its crushing gravity field, totally blocks the way through the tunnel. A traversable wormhole does not have a singularity blocking the tunnel or any crushing gravity field. Explorers would enter one side of the tunnel, travel through the throat, and exit the other side. Traversable wormholes also do not possess an event horizon, a region of high gravitational field strength separating the inside space surrounding the black hole's singularity from the outside universe. Once you go through a black hole's event horizon, you can never come back out because you will have to attain FTL speed to escape it. Not even light can escape from an event horizon. [p. 6] Figure 1. Intra-Universe Wormhole as a Hyperspace Shortcut Through Conventional Space. Traversable wormholes are creatures of classical general relativity theory allowing for very comfortable travel through the Cosmic Neighborhood. But from the viewpoint of modern physics, the Cosmic Neighborhood can encompass other universes, other space dimensions, and other times beyond the four-dimensional spacetime realm. Mankind has certainly not discovered all of the universe's facets and will need to continue to construct new experiments and technology in order to verify (or not) these undiscovered facets. Wormholes can possess normal or backward (in special cases) motion through time and normal or nonexistent gravitational stresses on space travelers, and their entry/exit openings (or throats) are spherically shaped, flat, cubic shaped, polyhedral shaped, generic shaped, and so forth. Why consider wormholes for travel through space, time, and other dimensions? All standard space propulsion engineering is based on Newton's three laws of motion, which is dependent on the expenditure of propellant to induce thrust-generating momentum transfer on a spacecraft. Many investigators have proposed interstellar propulsion schemes based on a variety of nuclear (fission, fusion, and pulsed) rockets, electric (ion or plasma) rockets, matter-antimatter annihilation rockets, solar or laser sails, fusion or laser ramjets, interstellar ion scoops, beamed energy propulsion (sails, rockets, and ramjets), and so forth. Many of these modes either have been experimentally tested at one time or another in our recent history or remain as theoretical proposals,

In this concept both the negative and positive energy pulses are ~ 10^-15 second duration. In principle a set of rapidly rotating mirrors could be arranged to separate the positive and negative energy pulses from each other. The light beam would be set to strike each mirror surface at a very shallow angle while the rotation would ensure that the negative energy pulses would be reflected at a slightly different angle from the positive energy pulses. A small spatial separation of the two different energy pulses would occur at some distance from the rotating mirror. Another system of mirrors would be needed to redirect the negative energy pulses to an isolated location and concentrate them there. See Figure 9 for an illustration of this concept. [Figure labels: Laser & LiNbO3 Resonator; Alternating Pulses of Negative & Positive Energy; Rotating Redirector Mirror System; Positive Energy Pulses; Negative Energy Pulses; Concentrated Negative Energy] Figure 9. Conceptual Squeezed Light Negative Energy Generator.

where p r is the outward radial pressure required to hold a wormhole throat open. The Gauss-Bonnet Theorem (discussed in Section II-A) predicted this result beforehand. Equation (11) is a result that is also due to the intrinsic nonlinearity of the general relativistic field equation. This nonlinearity also impacts the coupling of a finite spaceship mass with each side of a wormhole's throat (or the mouth on each side of the throat) leading to a specialized mass conservation law for the combined system of spacecraft and wormhole: when finite mass spaceships traverse a wormhole they alter the (equivalent) mass of the wormhole mouths they pass through (Reference 3). The entrance mouth absorbing the spacecraft gains (equivalent) mass while the exit mouth emitting it loses (equivalent) mass.(11) (This mass coupling and conservation law takes into account the possibility that spaceships traversing the wormhole may lose or gain some momentum and kinetic energy in the process, and it is assumed that the two mouths are sufficiently far apart that their mutual gravitational interaction is negligible.) This unusual result suggests, but does not prove, the possibility of a fundamental limit on the total mass that can traverse a wormhole. The coupled mass conservation law shows that for a sufficiently large net transfer of mass the final (equivalent) mass of the exit mouth becomes negative. This is actually a beneficial result because ANEC violations are required just to hold the wormhole throat open in the first place. If it appears that a runaway reaction might occur, then it would be prudent for wormhole engineers to simply “turn off” the wormhole for a brief moment and then “turn it back on” (i.e., “reset” the wormhole) to restart space transportation operations. It is on the basis of the foregoing discussion that traversable wormholes appear to be the most viable form of FTL transport. However, one still does not know how to construct a traversable wormhole because general relativity theory only provides a recipe for the essential geometric and material ingredients required to open and maintain one, but not the required assembly instructions. Will one need to pull a traversable wormhole out of the quantum spacetime foam and enlarge it to macroscopic scale or will there be need to use extremely large spacetime curvatures to “punch a hole” through space? Or are there construction techniques yet to be identified? The author is convinced that the answer can only be found through empirical studies designed to decide whether the present general relativistic recipe is enough to work with or an additional construction mechanism will be required. On physical grounds Equation (10) appears to be the correct negative energy/energy condition violation quantifier. However, further work is needed to establish whether Equation (10) is the correct quantifier to use overall and whether all (averaged) energy condition theorems can be extended to include it. On another note, Borde et al. (Reference 65) have recast the QI conjecture into a new program which seeks to study the allowed spatial distributions of negative energy density in quantum field theory. Their study models free massless scalar fields in flat two-dimensional Minkowski spacetime. Several explicit examples of spacetime averaged QI were studied to allow or rule out some particular model (spatial) distributions of negative energy. Their analysis showed that some geometric configurations of negative energy can either be ruled out or else constrained by the QI restrictions placed upon [footnote 11: Similar coupling and conservation results hold for the case of electrically charged matter that traverse a (charged or uncharged) wormhole.]

V. Conclusion: The Way Forward. More than 40 years elapsed between the late 1890s when the Curies first identified radioactive substances in their laboratory and when a neutron-catalyzed fission chain reaction - the world's first nuclear reactor - was demonstrated at the University of Chicago in 1939 by Enrico Fermi and Leo Szilard. Six more years would pass before the world's first nuclear bomb was successfully tested in New Mexico. The progress of science and technology is rapid, but highly dependent on adequate and sustained focus, effort, and support. On this basis, it is possible that a traversable wormhole can be demonstrated in the laboratory as long as there is a focused, sustained level of long-term research support. A game changer may appear that could dramatically accelerate or alter the direction of an experimental traversable wormhole program. Such a game changer could entail new physics that is predicted by a complete, comprehensive quantum gravity theory, or a quantum gravity theory that is a subset of a larger unified field theory (i.e., a finalized quantum superstring theory, or some other theory that replaces it), or a completely new theory for the quantum vacuum and its related spacetime physics (e.g., “emergent” spacetime/gravity theories (Reference 73, 74)). The new field of “emergent” spacetime/gravity suggests that gravitation is not a fundamental force of nature because, among many other considerations, of its extreme weakness relative to the other forces of nature. Instead, spacetime and gravitation are seen as emergent low-energy phenomenon, which arises from the collective action of much higher-energy phenomenon occurring in the quantum vacuum where Lorentz invariance and energy conservation may be violated in the trans-Planckian regime. One now knows empirically that the “emergent” low-energy vacuum within which one exists is in fact a rich quantum ether comprised of zero-point fluctuation fields that make it behave like a nonlinear optical medium endowed with paramagnetic, dichroic, birefringent, condensed [p. 35] matter, and many other fascinating properties (Reference 22-24, 26, 73-76). Therefore, if the emergent spacetime/gravity approach turns out to be correct, then there will likely be a direct consequence to the physics of traversable wormholes that could dramatically alter the mechanism by which they are created and/or mitigate the requirement for negative energy. Until such new approaches are established and testable predictions published by their proponents, one cannot speculate on how the physics of traversable wormholes will be affected. Therefore, it is beneficial to stick to the outcome of the present study in terms of quantum field theory and general relativity theory, and outline what needs to be accomplished going forward in order to demonstrate a traversable wormhole in the lab. Going forward toward the demonstration of a traversable wormhole will require the following: • Generating Negative Energy in the Lab: Our assessment concludes that we already make small amounts of negative energy in the lab, but we do not yet know if we can access larger amounts for extended periods of time over extended spatial distributions for the purpose of engineering a traversable wormhole. In this regard we propose the following options for further exploration. • Squeezed quantum vacuum generators: A dedicated research program to develop the two negative energy generator concepts described in Section III-B-2 will need to be established in order to evolve state-of-the-art quantum optics technology towards producing higher magnitudes of negative energy as well as special techniques required to separate out any positive energy fluxes that accompany the negative energy fluxes. Specifically, the Rabeau et al. (Reference 48, 49) and Ries et al. (Reference 50) experimental programs should be followed as a template toward this goal. Quantum optics technology via high power fiber lasers, resonators, amplifier stages, beam conditioning stages, etc., are rapidly advancing. So research should be conducted in parallel to invent additional ways to produce negative energy via innovative quantum optics. • Casimir effect: Even though the standard electromagnetic Casimir effect is feeble, and thus not likely to contribute to a traversable wormhole engineering program, there are still a number of other electromagnetic and non-electromagnetic Casimir effects described in Section III-B-4 that require further study. These other Casimir effects have not been explored with an eye toward testing them in the lab, and so there could be important new information yet to be uncovered. • Moving Mirrors (a.k.a. the dynamical Casimir effect): Even though this concept was identified (Section III-B-5) as being too feeble to produce any useful flux of negative energy, the observable effects due to the change in the boundary conditions (e.g., moving mirrors/cavity walls) of quantum fields provide crucial information on the quantum vacuum at the macroscopic level. Theoretical and laboratory efforts are underway to understand the dissipative effects of vacuum fluctuations (Reference 77-78). This dissipation mechanism should induce irradiation of photons, a phenomenon also known as the dynamical Casimir effect. This can be understood both as the creation of particles under non-adiabatic changes in the boundary conditions of quantum fields, or as classical parametric amplification with the zero-point energy of a vacuum field mode as an input state. More recent developments [p. 36] include models for the super-radiant amplification of photons with particular emphasis on its dynamics and the optimization of the involved parameters. Experimental concepts being pursued will try to reveal directly the presence of a non-empty vacuum by using a specifically designed device to amplify the virtual vacuum photons and produce real electromagnetic radiation via the parametric amplification of the vacuum fluctuations in an electromagnetic cavity. The ‘amplifier’ is a boundary undergoing an oscillation, and hence radiates energy due to the dissipative action against the vacuum photons. This line of investigation could serve as a very useful probe to explore the possibility of generating large fluxes of negative energy. It may be expected that a laboratory demonstration of the dynamical Casimir effect will occur before 2012. • Dirac field states: As described in Section III-A, this involves either the superposition of two single particle electron states or the superposition of two multi-electron-positron states (Reference 29, 30). This is still a nascent topic of study in quantum field theory. However, mankind already possesses a great deal of technology that is dedicated to the manipulation and storage of electrons and positrons via solid state/condensed matter devices and particle accelerators. This research topic should be supported in order to establish how it could contribute to an experimental traversable wormhole program. • Quantum coherence effects: Other types of quantum coherence effects not already identified or invented should be theoretically developed and explored for the possibility of finding new free-field or interacting field configurations that produce a significant magnitude of negative energy which could be produced by technological means. • Detecting Negative Energy in the Lab: In Section IV-C this paper identified proposals for observing negative energy in outer space and in the laboratory, but further work is needed to downscale astronomical techniques for use at the lab scale, and we need to firm up our understanding of how lab detectors will respond to negative energy in situ. A first step in the latter direction was recently proposed by Marecki (Reference 79) who generalized the analysis of the output of balanced homodyne detectors (BHDs). The most important feature of these devices is their ability to quantify the quantum vacuum fluctuations of the electric field because the output of BHDs provides information on the one- and two-point functions of arbitrary states of quantum fields. Marecki computed the two-point function and the associated spectral density for the ground state of the quantum electric field in Casimir geometries, and predicts a position- and frequency-dependent pattern of BHD responses if a device of this type is placed inside a Casimir cavity. The proposed device allows for the direct detection of quantum vacuum fluctuations and provides a spatial mapping of the negative energy contained inside the cavity. This offers a potential new characterization of ground states in Casimir geometries, which would provide an understanding of the negative energy densities present in some regions in these geometries. • Trapping and Storing Negative Energy: Ford and Roman (Reference 10) have only superficially addressed this topic, and there is very little technical literature that addresses it fully. A theoretical program to develop the physics and technology of trapping and storing negative energy will need to be supported, and such a program should be guided by the use of laboratory detectors such as the one proposed in the [p. 37] previous section. However, it is the opinion of the author that free-space negative energy sources appear to be a more desirable option for building traversable wormholes than stored negative energy. • Constructing Traversable Wormholes in the Lab: Einstein's General Theory of Relativity does not provide instructions on how to construct a traversable wormhole in space or inside a laboratory vacuum vessel. The Einstein general relativistic field equation only provides a prescription for designing a special, localized spacetime geometry and calculating the physical characteristics of a source of matter that is required to induce it. If one “zaps” a region of empty space with a beam of negative energy, will a traversable wormhole appear? One doesn't know. Maybe one has to poke a hole in space with an intense beam of negative energy, or maybe we have to use the negative energy to inflate a quantum spacetime fluctuation (allegedly in the form of a “geometric foam”). Theoretical studies need to be implemented to address this question and the author believes that empirical studies will be necessary to find the answer once we develop an intense source of negative energy.