“*The vacuum holds the key to a full understanding of the forces of nature.” *P.C.W. Davies, Superforce (Simon and Schuster, New York, 1985). P.104

Modern quantum theory has its earliest inception in the discovery, by Max Planck, of the very real and constitutive zero-point energy of material systems. Because material systems are just patterned excitations of underlying quantum fields, the zero-point energy applies equally to the vacuum state of these quantum fields and there is an ever-present zero-point field. It is also interesting that despite being over a century old, quantum mechanics seems to be regarded by many as an advanced, even cutting-edge theory; perhaps because despite being an old and known provisional theory that will ultimately be supplanted, it still holds many seemingly mysterious and inexplicable results, like the zero-point energy of quantum fields. Indeed, the quantum vacuum is still generally not well understood, even by physicists, many of whom seem to be inclined to regard the zero-point energy of free space as trivial or virtual, and eyebrows are certainly raised when it is mentioned—following the facts of quantum theory—that we live in a veritable limitless sea of energy and that this energy can be harnessed. Yet, as we will see, some scientists and inventors have already moved far-beyond the debate over the materiality of the vacuum; they are actively engineering spacetime with devices that purport to work by tapping the zero-point energy fluctuations of the quantum vacuum.

There has been a long history of theoretical development around harnessing the potential of the quantum vacuum for energy generation and propellant-less propulsion. Pioneering studies have examined the possibility of using known modalities of quantum vacuum engineering techniques to extract zero-point energy from the field and store it in a battery [Figure 1- Forward 1984, Puthoff 1993]. More recent works have analyzed the role of quantum vacuum fluctuations in various quantum technology platforms: as described in Jordan *et al*.’s study of *Many-body quantum vacuum fluctuation engines* “*It has been shown that zero-point fluctuations stemming from bosonic environments permit the rectification of electrical current, producing work [Henriet et al. 2015], and a superconducting circuit-based thermal engine relying on the presence of zero-point fluctuations of a microwave cavity [Hofer et al. 2016]. These works demonstrated that incorporating vacuum fluctuations in the design principles of engines and batteries is a scientifically sound and promising direction to pursue as quantum technology continues to develop*.” In their study Jordan *et al. *describe a plausible methodology to design a many-bodied quantum engine “*powered by the energy difference between the entangled ground state of the interacting system and local separable states*“.

_{Figure 1. Spiral design for a vacuum-fluctuation battery. }_{Forward’s concept of a zero-point energy quantum vacuum fluctuation battery; schematic from his 1984 research publication. R. L. Forward, Extracting electrical energy from the vacuum by cohesion of charged foliated conductors, Physical Review B 30, 1700 (1984).}

However, harnessing the zero-point energy of quantum vacuum fluctuations and geometrodynamic engineering has moved beyond such theoretical considerations with direct and demonstrable applications. Earlier this year researchers at Ghent University in Belgium announced the invention of an ultra-fast random number generator that uses quantum fluctuations—in which variations driven by pairs of particles and antiparticles that form and then annihilate can be used to generate random numbers up to 200 times faster than available commercial devices can [1]. And just this July researchers at MIT demonstrated that quantum vacuum fluctuations could be controlled with a laser and described utilization of this method to harness random fluctuations of quantum vacuum energy (in free space) to generate random bit strings for probabilistic computing [2]. These methodologies directly harnessing and utilizing the zero-point energy of the quantum vacuum demonstrate (1) that the quantum vacuum energy density is not trivial or virtual, and (2) that techniques to engineer the stochastic fluctuations of the zero-point energy field of the quantum vacuum are feasible, and indeed moving towards direct technological applications.

With the advent of spacetime engineering capabilities that come from understanding quantum vacuum zero-point energy and the nature of gravity we will see the dawn of technologies that will fundamentally reshape our civilization and take us to the stars.

## Planck, Einstein, Nernst & Zero-point Energy

“*The existence of a zero-point energy of size 1/2 hv [is] probable.*” –Albert Einstein and Otto Stern (1913) [3]

All material systems are comprised of elementary harmonic oscillators—or more precisely, harmonic angular frequency of spin—be they atoms or subatomic particles. At the turn of the 20^{th} century, it was discovered that these harmonic oscillators have an indelible energy value even at the zero-point level, where classically there should be no energy. Since material systems are just patterned excitations of an underlying quantum field, these vibrational elements extend to the description of quantum fields such that quantum harmonic oscillators comprise the very fabric / materiality of space and the associated zero-point energy is present in all fields. For example, the zero-point energy of the electromagnetic field, sometimes simply referred to as *the *zero-point field (ZPF). Since this energy remains even when all classical sources of mass, energy, or force have been removed from a given space—in what would otherwise be a vacuum—zero-point energy gives the vacuum of space an indelible energy density, such that free space is not empty but is a quantum vacuum: filled with constitutive energetic fluctuations of quantum fields even at the vacuum / ground state / zero-point level.

The modern understanding of the quantum vacuum and non-zero vacuum state energy fluctuations have beginnings in circa 1912 – 1913 with the research of Planck, Nernst (the father of the quantum vacuum), Einstein & Stern into blackbody radiation, zero-point energy of harmonic oscillators, and the electromagnetic field. The elucidation of zero-point energy (*n**ullpunktsenergie*) by Planck and Einstein predates the formalism of quantum mechanics, although in contemporary physics zero-point energy is most closely associated with quantum harmonic oscillators and vacuum fluctuations of matter fields and force fields (whose quanta are fermions and bosons, respectively). Connected with the energetic fluctuations of the electromagnetic vacuum are the geometrodynamic fluctuations of the spacetime manifold, which generates continual volumes of high positive and negative curvature—resulting in a multiply-connected spacetime geometry of micro-wormholes / Planck-scale Einstein-Rosen bridges—what John Archibald Wheeler termed as quantum spacetime foam.

It is indicative of the prevalent misunderstanding regarding the zero-point energy of free space that when quantum vacuum fluctuations are discussed they are described as occurring as a result of the Heisenberg uncertainty principle; this is in error. **In fact, contrary to popular belief, the**** Heisenberg uncertainty principle is a consequence—not the source of—vacuum fluctuations of the zero-point energy field (**Haramein *et al*.,** **the origin of mass and nature of gravity**, **pre-print, 2023**). In the QFT formulation (e.g., for a dipole oscillator) the position and momentum operators are ***non-commutative***, which roughly means they do not give the same results. Zero-point energy is required within this formalism to maintain the non-**

**commutativity**

**of the position and momentum operators. It then follows that the foundations of quantum mechanics and the uncertainty principle are firmly rooted in the dynamics of ZPE vacuum fluctuations that define the bath (or field) in which particles appear, evolve, and interact.**

The inception of the concept of zero-point energy is found in Planck’s work on the quantization of energy (by Planck’s constant , the birth of quantum theory) to resolve the high-frequency divergence of radiative energy density that occurred in classical predictions of the spectral density of electromagnetic radiation for a blackbody, what was referred to as the ultraviolet catastrophe or the blackbody problem [4]. In analysis of the entropy of harmonic oscillators comprising a black body (the atoms of an absorbing material) Planck discovered—contrary to what was expected—that as the temperature of a material system goes to zero the mechanical oscillators of that body retain a non-zero energy value. As such, from consideration of the relationship of entropy to the average energy of an elementary radiator (a material oscillator) Planck discovered the existence of zero-point energy, for Planck’s mathematical analysis and solution to the blackbody problem revealed that even at zero temperature (the *nullpunkt*, or zero-point), there is still an energy in the material oscillator.

This result was obtained from theoretical consideration to resolve the ultraviolet catastrophe, however now there are ample direct observations of intrinsic zero-point energy, evidenced in the behavior of material systems under super-cooled conditions: from Bose-Einstein condensates, electron Cooper pairs in superconductors, to superfluidity. For example, liquid helium will not freeze regardless of temperature at standard atmospheric pressure due to the zero-point energy that remains even as the temperature approaches absolute zero Kelvin—instead, when cooled below its Lambda point helium becomes a superfluid. Note, the non-classical behavior and properties of superfluid and superconducting systems have significant relevance to considerations of the nature of the quantum vacuum as in some approaches in theoretical physics, such as superfluid vacuum theory (Bose-Einstein condensate vacuum theory), the vacuum is modeled as a superfluid [5,6,7].

Planck interpreted his results as demonstrating the peculiarities of the emitting system and insisted that they were not describing an intrinsic property of light itself (Cramer J.G., The Quantum Handshake: Entanglement, Nonlocality and Transactions. 2016). However, this view was challenged by Einstein in 1905 with his study of the emission of electrons from metals illuminated by light, now known as the photoelectric effect. Einstein defined quanta of energy radiation by putting forth the heuristic argument that the emission and absorption of Planck oscillators changes by discrete intervals which are integral multiples of Planck’s constant *h* and the frequency* v*, essentially beginning the concept of discretization of electromagnetic radiation, which he referred to as the photon (so, when it is proclaimed that Einstein “did not like quantum mechanics”, remember that he was the founder of QM). This enabled Einstein to make specific predictions from his elucidated photoelectric effect, an effect of which is important in consideration of the coupling of matter with quantum vacuum fluctuations involved with absorption and emission of electromagnetic quanta.

In studying the nature of dipole oscillators, Einstein and Stern applied a zero-point energy to the average energy of a dipole oscillator. When they applied this zero-point energy factor to dipole oscillators they were able to exactly produce the Planck spectrum of blackbody radiation. Interestingly, Einstein and Stern’s zero-point energy value was two times that previously found by Planck. This means that even though they did not realize it at the time Einstein and Stern discovered the zero-point energy of field modes—the zero-point field—because the zero-point motion of a material dipole oscillator is coupled to the zero-point oscillations of the field, and hence their derived value was twice that of Planck’s.

However, despite having been the originators of zero-point energy, neither Planck nor Einstein & Stern ever suggested that there might be a zero-point field. Instead, the first discussion of this possibility is attributed to Walther Nernst in 1916 [7]. Although less known than his contemporaries Einstein and Planck, Nernst was a seminal figure in modern physics and is viewed by many as the grandfather of concepts like the quantum vacuum and the cosmological constant; hot topics of research to this day.

## Why is Zero-point Energy and the Quantum Vacuum Relevant?

So, we see the foundational aspect of zero-point energy. Indeed, physicist Nassim Haramein and his research team have recently delineated The Origins of Mass & The Nature of Gravity, explaining:

*While Einstein field equations tell us that gravity is the result of the curvature of spacetime from a source term given as a stress energy tensor or mass-energy, it neither tells us the origin of this mass nor the nature of spacetime. Furthermore, it tells us that certain regions of spacetime can reach infinite curvature from an infinite energy density as in the singularity of a black hole. On the other hand, early exploration of quantum mechanics demonstrated that the electromagnetic quantum vacuum ground state is violently fluctuating resulting, when summing on all modes, in an infinite amount of energy. Here we demonstrate that this energy density is the source of mass and forces that ensue whether at the classical scale as in gravity, or at the quantum scale as in the confining force.*

*Utilizing the correlation functions, we examine Max Planck early discovery of zero-point energy (ZPE) in the context of the black body radiation of an oscillator. We find that ZPE, which diverges when all modes are considered resulting in an infinite electromagnetic energy density, is in fact in the order of the Planck density when considering General Relativity (GR) and quantum geometrodynamics providing a natural cut-off at the Planck scale. While in free space this energy density is not apparent at classical scale, in highly coherent phases like in resonant cavities, this energy density becomes significant and measurable for instance in the case of Casimir and dynamical Casimir effect. Furthermore, the consistency of the mathematical framework of quantum theory requires ZPE to maintain the non-commutativity of the operators, essential for particle stability.*_{ }

_{Haramein, et. al., 2023. The Origins of Mass & The Nature of Gravity Abstract. Accessed online via Spacefed.com, August 8th 2023.}

In addition to resolving fundamental considerations at the heart of physics, like the origin of mass and the nature of gravity, an understanding of zero-point energy and the quantum vacuum will enable the engineering of technologies that will revolutionize human civilization: like gravity control for advanced (non-chemical) propulsion systems and extraction of energy from the zero-point field. The energy density of free space has the potential to be the ultimate energy source for humanity, indeed just as it is the ultimate energy source for all physical phenomena.

To get an idea of what kind of energy density we are talking about we can calculate the vacuum energy expectation value (VEV). When all field modes of the quantum vacuum are summed for a given unit volume of space the VEV is infinite. In Quantum Electrodynamics and Stochastic Electrodynamics there is a renormalization procedure that is utilized (*ad hoc*) in which a cut-off term of the Planck frequency (~10^{42 }Hz) is introduced to limit the allowable field modes of vacuum oscillations, so that the total energy density of the quantum vacuum is calculated to be around 10^{113 }joules per cubic meter. This is an unimaginably large amount of energy.

While initially, a vacuum expectation value of infinite zero-point energy density may seem to be a non-physical result, there are theoretical (as well as observational) reasons to believe that the vacuum state truly does have an extremely large zero-point energy density. As early as 1907 Oliver Lodge had calculated values for the energy of free space via naive calculations of the density of the æther[1]—the quantum vacuum being a transmogrified æther—of 10^{26} J/cm^{-3} or (by the E = mc^{2} equivalency) 10,000 tons cm^{-3} [8]. As he described the energy density of space: “*This is equivalent to saying that 3 X 10 ^{17}kWh, or the total output of a million-kilowatt power station for 30 million years, exists permanently, and at present inaccessibly, in every cubic millimeter of space*” [9, 10].

*[1] At the turn of the 20 ^{th} century electromagnetic waves were understood to propagate in a substantive medium called the luminiferous æther.*

Regarding the extremely large energy density values he calculated (given the early and limited conceptions of the nature of the field and zero-point energy density of his era) Lodge further commented that: “*There is nothing paradoxical, nor, so far as I can see, improbable, about these figures… and the inertia *[i.e., mass]* of matter must be a mere residual fraction of the inertia of the continuous incompressible complex fluid, of which it is hypothetically composed, and in which it moves.*” Lodge’s calculation of the energy density of free space was based on the then presumptive properties of the ubiquitous æther medium and the æthereal constants of magnetic permeability and the electric inductivity of free space, so it is interesting to see that while he calculated a seemingly extremely large energy density, it is still some ~10^{87 }times smaller than contemporaneous VEV calculations (when the Planck frequency is utilized as a cut-off value for allowable field modes of the ZPE field).

If we can harness even a minute fraction of this energy density, it would power all of humanity’s global energy requirements indefinitely and would elevate us to at least a Type I civilization on the Kardashev Scale (right now we are a Type 0 civilization, being mostly reliant on the combustion of dead plant matter for energy generation). Before even considering the technological methodologies that are already directly accessing and harnessing the substantive energy of free space, it can be noted that there are no theoretical objections that would deny the ability to engineer and harness vacuum energy. As physicist Harold Puthoff states it “*the basic thermodynamics involved in these proposals* [to extract energy from electromagnetic zero-point radiation] *is analyzed and clarified here, with the conclusion that, yes, in principle, these proposals are correct*” [11].

Even among ardent skeptics, like Matt Visser of Washington University in St. Louis, it is acknowledged that**: **“it* definitely is possible to manipulate the vacuum energy. Any objects that change the vacuum energy (electrical conductors, dielectrics and gravitational fields, for instance) distort the quantum mechanical vacuum state. These changes in the vacuum energy are often easier to calculate than the total vacuum energy itself. Sometimes we can even measure these changes in the vacuum energy in laboratory experiments.” *What is the ‘zero-point energy’ (or ‘vacuum energy’) in quantum physics? Is it really possible that we could harness this energy?

We see then that the ZPE of the quantum vacuum is not trivial and can be engineered via technological means. We have highlighted a number of such methodologies that directly work with and harness the energy density of free space, such as: the Casimir Diode, the quantum energy teleportation protocol, and the Schwinger Effect in graphene superlattices, to name a few examples (in addition to the recent applications discussed in the introduction).

Understanding the nature of quantum vacuum fluctuations of the zero-point energy field is fundamental to understanding quantum field theory, the spin and geometrization of space, and the unification of the two in quantum gravity and unified physics. We are now moving into an era where there is sufficient understanding of QVF and ZPF that there is direct technological advancement from application of the unified physics models. Here, we will examine some of the quantum vacuum energy extraction and spacetime engineering theories and applications that are demonstrable first-iteration techniques that are leading the way to future technologies that will see the full realization of harnessing the zero-point energy field and controlling the gravitational metric of spacetime.

## Quantum Vacuum Energy Extraction

By far the Casimir effect is the most widely utilized phenomenon for proposals and applied techniques to extract or harness energy from the zero-point field [12]. In 1948 Hendrick Casimir described how an attractive force would be generated between two perfectly conducting plates by virtue of suppression of certain modes of quantum vacuum fluctuations, what is now called the *Casimir Effect*. Casimir discovered the force after studying the mathematics of classical electrodynamics for the change of electromagnetic zero-point energy when the configuration of the perfectly conducting plates had a specific gap volume (cubic cavity) between them. The Casimir effect has since been experimentally observed and validated [13], including the *dynamical Casimir effect*, in which rapidly oscillating mirrors generate a time-dependent boundary condition of the zero-point electromagnetic field, amplifying vacuum fluctuations resulting in the production of photons [14].

_{Figure 2. }_{In quantum field theory, the Casimir effect (or Casimir force) is a physical force acting on the macroscopic boundaries of a confined space which arises from the quantum fluctuations of a field. It is named after the Dutch physicist Hendrik Casimir, who predicted the effect for electromagnetic systems in 1948. A typical example is of two uncharged conductive plates in a vacuum, placed a few nanometers apart. In a classical description, the lack of an external field means that there is no field between the plates, and no force would be measured between them. When this field is instead studied using the quantum electrodynamic vacuum, it is seen that the plates do affect the virtual photons which constitute the field and generate a net force – either an attraction or a repulsion depending on the specific arrangement of the two plates. Although the Casimir effect can be expressed in terms of virtual particles interacting with the objects, it is best described and more easily calculated in terms of the zero-point energy of a quantized field in the intervening space between the objects. This force has been measured and is a striking example of an effect captured formally by second quantization. Source: Wikipedia Casimir effect.}

As such, the Casimir effect is a well-known example of violation of the strong energy condition, generating a local negative energy density in space—which may have such natural effects as stabilizing the tunnels of Einstein-Rosen bridges and other exotic geometrodynamic configurations. As such, it serves as an experimentally verified proof-of-concept for many advanced spacetime propulsion technologies like wormholes, warp drives, and for modulating vacuum field modes for ZPE extraction.

One of the most promising methods for converting energy from the electromagnetic quantum vacuum is by passing gases through Casimir cavities such that the Lamb shift in their electron orbital energy levels is suppressed—due to cancellation of normally interacting vacuum field modes within the Casimir cavity—resulting in an emission or release of energy by the atoms of the gas [15]. As described in U.S. Patent 7,379,286 “when atoms enter into suitable micro-Casimir cavities a decrease in the orbital energies of electrons in atoms will thus occur” and this energy can be captured [16]. The inventors through their company the Jovion Corporation have constructed such devices and tested their electromagnetic quantum vacuum energy conversion capabilities.

The inventors further explain that “upon emergence form such micro-Casimir cavities the atoms will be re-energized by the ambient electromagnetic quantum vacuum. In this way energy is extracted locally and replenished globally from and by the electromagnetic quantum vacuum. This process may be repeated an unlimited number of times. This process is also consistent with the conservation of energy in that all usable energy does come at the expense of the energy content of the electromagnetic quantum vacuum. Similar effects may be produced by acting upon molecular bonds. Devices are described in which gas is recycled through a multiplicity of Casimir cavities. The disclosed devices are scalable in size and energy output for applications ranging from replacements for small batteries to power plant sized generators of electricity.”

_{Figure 3. }_{Schematic representation of the vacuum-energy extraction process. Gas circulates through the system. The electronic orbitals of the gas atoms spin down to a lower level as the gas enters the Casimir cavity, radiating the excess energy to the absorber. Upon exiting the cavity, the orbitals are re-energized by the ambient zero-point field. In this way, energy is collected from the ambient zero-point field and deposited on the absorber. Source: [15] O. Dmitriyeva and G. Moddel, “Test of Zero-point Energy Emission from Gases Flowing Through Casimir Cavities,” Physics Procedia, vol. 38, pp. 8–17, 2012, doi: 10.1016/j.phpro.2012.08.007.}

## Advanced Space Propulsion Based on Vacuum (Spacetime Metric) Engineering

*The concept of “engineering the vacuum” found its first expression in the physics literature when it was introduced by Nobelist T.D. Lee in his textbook Particle Physics and Introduction to Field Theory [17]. There he stated: “The experimental method to alter the properties of the vacuum may be called vacuum engineering…. If indeed we are able to alter the vacuum, then we may encounter new phenomena, totally unexpected.” This legitimization of the vacuum engineering concept was based on the recognition that the vacuum is characterized by parameters and structure that leave no doubt that it constitutes an energetic and structured medium in its own right. Foremost among these are that (1) within the context of quantum theory the vacuum is the seat of energetic particle and field fluctuations, and (2) within the context of general relativity the vacuum is the seat of a spacetime structure (metric) that encodes the distribution of matter and energy. *[18]

_{Figure}_{ 4. Alcubierre warp drive metric. Alcubierre derived a spacetime metric motivated by cosmological inflation that would allow arbitrarily short travel times between two distant points in space. The behavior of the warp drive metric provides for the simultaneous expansion of space behind the spacecraft and a corresponding contraction of space in front of the spacecraft. The warp drive spacecraft would thus appear to be “surfing on a wave” of spacetime geometry. By appropriate structuring of the metric the spacecraft can be made to exhibit an arbitrarily large apparent faster-than-light speed as viewed by external observers without violating the local speed-of-light constraint within the spacetime-altered region. Furthermore, the Alcubierre solution showed that the proper (experienced) acceleration along the spaceship’s path would be zero, and that the spaceship would suffer no time dilation, highly desirable features for interstellar travel. In order to implement a warp drive, one would have to construct a “warp bubble” that surrounded the spacecraft by generating a thin-shell or surface layer of exotic matter, i.e., a quantum field having negative energy and/or negative pressure. Image source and description from: [18]. }

The capabilities to engineer the spacetime metric come from being able to manipulate the energy density of quantum vacuum fluctuations, for instance generating a negative energy density for warp metric gravitational curvature—negative energy density or violation of the strong energy condition being achievable via the Casimir force, as an example. In this way, energy extraction from the vacuum, or more precisely extracting work from the zero-point field is one-and-the same with geometrodynamic engineering for advanced propulsion via gravitational control. i.e., engineering the spacetime metric. There are many potential means to generate gradients in the quantum vacuum energy density for spacetime engineering (and energy extraction); here, we will look at a few that are already in practice and nearing functional applications.

## Resonance in Closed Electrical Systems to Modulate QVF

For many years there have been experimentally validated indications that thrust can be obtained from closed electrical systems, opening the possibility for novel propulsion methods that do not rely on chemical combustion or emissions of propellants. One example is the EmDrive [19]: a conically shaped microwave resonant cavity design in which it has been demonstrated in prototypes that the system produces a propellantless-thrust towards its narrow end. This has been independently replicated in at least two laboratories, NASA’s Eagleworks lab [20] and China Academy of Space Technology [21].

_{Figure 5. Basic layout of the EmDrive resonant cavity. }_{The system uses a cylindrical tapered resonance cavity as a thruster and uses an integrated microwave source to generate continuous EM wave so that the EM wave is radiated into and then reflected from the thruster to form a pure standing wave with amplified wave amplitude. The pure standing wave produces a non-uniform EM pressure distribution on the inner surface of the thruster. Consequently, a non-zero net EM thrust exerting on the symmetric axis and directing to the minor end plate of the thruster appears. In experiments a magnetron is used as a microwave source with an output microwave power of 2.45 GHz frequency. The generated net EM thrust is measured using a force-feedback test stand. The developed thruster system is experimentally demonstrated to produce thrust from 70 to 720 mN when the microwave output power is from 80 to 2500 W. Description from: Juan Y., Yu-Quan W., Peng-Fei L., Yang W., Yun-Min W., and Yan-Jie M., “Net thrust measurement of propellantless microwave thruster,” Acta Phys. Sin., vol. 61, no. 11, pp. 110301–110301, Jun. 2012, doi: 10.7498/aps.61.110301.}

Sonny White, who led the empirical tests at NASA’s Eagleworks laboratory explains the initially seeming anomalous thrust of the EmDrive as a natural outcome of anisotropic microwave standing waves that can be operationally described within vacuum-based pilot-wave theories or stochastic electrodynamics [22], in which it is possible to do/extract work on/from the vacuum (spacetime engineering), and thereby to push off of the quantum vacuum and preserve the laws of conservation of energy and conservation of momentum. Sonny attributed the propellantless-thrust of the microwave resonator to the EmDrive’s ability to “push off” of quantum vacuum fluctuations of the zero-point field, such that the thruster generates a volumetric body force and moves in one direction while a hydrodynamic wake in the superfluid quantum vacuum is established that moves in the other direction.

Similar to the EmDrive system, an asymmetric capacitor design that produces propellantless-thrust called a Mach Effect Thruster (MET) has been under development [23, 24] and is featured on NASA’s Spacetech website as a novel form of propulsion “based on peer-reviewed, technically credible physics”. Thrust can be obtained if an AC current is fed into a Piezoelectric Material (PZT) sandwiched between a thick conducting plate and a thin one. The thrust is always towards the thick plate.

_{Figure 6. }_{Mach Effect Thruster Schematic by J.F. Woodward: The current embodiment of the Mach-Effect thruster consists of a stack of piezo discs that is similar in design to typical actuators using ferroelectric (PZT=Lead Zirconate Titanate) materials, which are sold by many suppliers e.g. for ultrasonic applications. In general, if an electric field is applied across such PZT discs, they expand and contract depending on the field strength and direction of the field. The piezo/PZT stack is made of several discs that are mechanically connected in series but electrically connected in parallel (i.e. all discs have the same electric potential applied between their electrodes). This is achieved by always switching the polarity from disc to disc such that every electrode faces another electrode with the same polarity to avoid electric short circuits. Woodward uses brass electrodes which are glued with epoxy between each disc. The whole assembly is clamped with stainless steel screws between two end caps, a larger one made from brass with threaded holes and a smaller one made from aluminum. The screws are tightened to ensure that the piezo stack is well compressed between the stiff end caps. Source: Brian Wang, 2017. Mach Effect Propulsion Replication and modeling that matches experimentation. NextBIGfuture.com }

Martin Tajmar of the of the SpaceDrive Project has replicated peer-reviewed published reports of tests that measured small thrusts apparently produced by the EmDrive and Mach Effect Thruster devices, and while his research team did measure the same values as reported in previous reports, they attributed the anomalous force to vibrational artefacts that they were able to identify with the extremely high precision and control of their torsional balance / test set-up (First Results on EmDrive and Mach-Effect Thrusters, and Mach-Effect Thruster Experiments on High-Precision Balances in Vacuum). The results of the SpaceDrive Project’s testing demonstrates the challenges of confirming true positives of micro-force thrust in Earth-bound laboratory experiments (even under vacuum conditions). As we will see, this is one reason why the ultimate laboratory to test these unconventional (propellantless) propulsion systems is to test them in the micro-gravity low-magnetic field environment of space.

## Modified Inertia from a Hubble-scale Casimir Effect: The Horizon-Drive

Inventor Mike McCulloch has demonstrated that Woodward JF’s hypothesis of Mach gravitationally modified inertia does not precisely predict the observed thrust, being in error by several orders of magnitude [25]; and instead has precisely predicted the Mach Effect, as well as the thrust of the EmDrive, via his theory of quantized inertia in which dynamics arise solely from a push on objects by the quantum vacuum, which can be made more intense by high acceleration (Unruh radiation) and made non-uniform in space either by matter (to explain gravity) or relativistic acceleration-dependent Rindler horizons (to explain inertia). Mike McCulloch claims that his theory predicts galaxy rotation without dark matter and without any adjustment [26-29], and that the theory of quantized inertia implies that it is possible to produce new dynamics by artificially creating horizons which damp the quantum vacuum, making it inhomogeneous and so, able to push on objects. This kind of propulsion—a QI- or horizon-drive—is the embodiment of vacuum energy spacetime engineering and when operational will enable propellant-less propulsion of spacecraft and enable interstellar travel since speeds close to c could be achieved without the need to also overcome the inertia of heavy fuel [18].

Unlike the force generated in nanoscale volumes by conventional Casimir forces, the Horizon Drive is a Hubble-scale Casimir effect that generates a damping of the quantum vacuum via producing a Rindler horizon that results from acceleration, generating Unruh waves; McCulloch has theorized that inertia is due to Unruh radiation [30] (due to Einstein’s equivalence principle, acceleration and a gravitational field are equivalent, so just as an event horizon will be generated from the gravitational field of a black hole, resulting in Hawking radiation, acceleration will generate a Rindler horizon producing the equivalent of Hawking radiation in an accelerating frame of reference: Unruh radiation).

_{Figure 7. }_{Equivalence of Hawking and Unruh radiation, since a gravitational field and acceleration are equivalent. The radiation is one-and-the-same, thus referred to as Hawking-Unruh radiation.}

The Horizon Drive, or Quantum Vacuum Thruster, is purported to work by reducing the Unruh radiation on the side of an accelerating object in which the dynamical Rindler event horizon is formed: for example, if an object is accelerated to the right a Rindler event horizon forms on its left. The Unruh radiation is reduced on this left side of the accelerating object via a Hubble-scale Casimir effect, whereby an imbalance in the radiation pressure on the object, from the quantum vacuum fluctuations of the zero-point energy field, generate a net force that opposes acceleration, i.e., inertia. Inertia can be overcome, and a net force generated in the direction of acceleration by utilization of metamaterials or an asymmetric resonant cavity that results in a asymmetric Casimir force. Regarding the latter, imagine that instead of the parallel plates in the Casimir force being perfectly parallel, they are brought into a v-shaped configuration, such that Casimir force will be asymmetric and generate a net force at one end of the system. Similarly, an artificial horizon can be generated when high acceleration matter or electromagnetic radiation is confined inside an asymmetric cavity, producing thrust [31] (Figure 8).

_{Figure 8. }_{An asymmetrical resonant metal cavity. Laboratory experiments have shown that such asymmetric metal cavities with strong electromagnetic fields resonating within them (emdrives) result in an unexpected thrust towards the narrower ends. Quantized Inertia predicts that if the asymmetric metal cavities are as small as 129nm then a thrust comparable to gravity can be obtained even from the unexcited zero point field. This implies that if a material was constructed with arrays of asymmetric nano-cavities, then the force would be enough to levitate that material. Source: M. E. McCulloch, “Can Nano-Materials Push Oﬀ the Vacuum?,” PROGRESS IN PHYSICS. Volume 16 (2020). http://www.ptep-online.com/2020/PP-60-02.PDF}

## Putting Spacetime Engineering and Quantized Inertia to the Test

Like Sawyer’s EmDrive, Woodward’s Mach Effect Thruster, and other quantum vacuum modulation technologies, McCulloch’s Horizon Drive / Quantum Vacuum Thruster are not just theory. The company IVO Ltd. has developed the technology into a device they call the *Quantum Drive*. The Quantum Drive has been tested and the resulting thrust analyzed over nearly 100 of hours of vacuum chamber experiments, and now the IVO research team are ready to put the pure electric (zero fuel) propulsion technology to the ultimate test with a planned October 2023 launch aboard a SpaceX rocket. The Quantum Drive will be tested this October to see if it can generate the propellantless-thrust and maneuver a satellite in low Earth orbit.

_{Figure 9. }_{Prototypes of the quantum drive, which will be tested in low Earth orbit this October 2023. Designed by IVO Ltd., an electronics prototyping company, the promising yet controversial Quantum Drive could change the future of space travel and, if proven to work, would potentially rewrite or expand many of the accepted principles of inertia and motion that have existed for centuries.}

Once in low Earth orbit, the Quantum Drives attached to the satellite—for redundancy there are two drives in two different configurations—will be powered on (harnessing electromagnetic energy captured from solar panels) and any changes in the orbital altitude measured by onboard sensors will demonstrate functionality of the propellantless-thruster systems. Positive results will herald a veritable new age for humanity’s space exploration, because we are extremely limited in our travel range due to the requirement of hauling massive amounts of chemical propellant. A “reactionless” drive, even if just producing minimal amounts of thrust like the current iteration of the Quantum Drive, will be a game changer. Because in the low-gravity environment of space, continuous small thrust quickly builds to extremely high velocities, especially when it does not require the acceleration of the fuel supply itself and limited by how much chemical propellant is available. Even more so, a functional device is a proof-of-concept of vacuum engineering technologies, and when it is seen that the zero-point energy field is a very real source of energy and novel chemical-free propulsion (like gravity control), there will be an inevitable flood of interest into further developing these technologies and formalizing the unified physics behind them—in which mass, inertia, gravity, and even the speed of light is produced from the properties of the quantum vacuum energy density.

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