Nuts and Bolts 31/10/13

Haven't done much Physics the last 2 months or so, been too busy with a Marine Engineering course I'm doing at the Hunter Institute - TAFE at Newcastle, this is towards getting my next Chief Engineer's licence. Some random photos below of the marine engineering workshop, Newcastle and the maritime action on the busy harbour (click for bigger versions). Impressive fleet of tugboats they have there. The wineyards up the Hunter Valley are also worth a visit.

 

 

                  

 

Is Gravity Control Propulsion viable? Part 6

Thought I might have some fun, I was thinking on some of the questions Marc Millis asked in his talk on Space Drives and Gravity Control Propulsion and it is useful to address his questions from the point of view of the model currently being worked on to see if there are any major logical inconsistencies with current Physics and if so why and if they can be addressed. Several screen grabs from Marc's talk are shown below to address the questions put forward. Note that I am answering the questions with the modified EMQG model in mind (which at this stage remember is a hypothesis which may have errors) however here we go.

Luke's Landspeeder (from the Star Wars fictional movie) has the ability to levitate above the ground and has some kind of jet engines to propel it forward. Will the frog get squeeshed if the speeder went over it?

No. The frog will become weightless while it is in the speeder's volume of influence on the local spacetime metric so the frog should survive. If the speeder parked above the frog, the frog would just be floating underneath the speeder as if it was in a space station in orbit. As the speeder approaches the frog, part of the frog's body will have weight and the other part will feel weightless which might confuse the frog for a moment (interestingly enough levitating a live frog on Earth has been done in the lab via different means: direct diamagnetic levitation). Note that Luke and C3PO will also feel weightless inside the speeder but a bird flying above the speeder outside the volume of influence will need to fly as normal to stop falling towards the ground.

What will happen to the speeder when it encounters the obstacles forward? It will clear the smaller ones but will crash into the higher ones unless Luke makes an altitude adjustment to the speeder. The GCP field of influence will act on the local spacetime metric causing objects to become weightless within, this may be a problem obstruction wise with loose objects if there are other influences involved such as wind etc. 

Which path will the speeder follow across the cliff? The green path, the speeder will go straight across as if there was no cliff at all. 

When the speeder is parked will it shoot off if pushed? (it appears rigid in the movie when parked). Momentum is conserved, there is no difference pushing the speeder in free space or at ground level when parked, it will drift away slowly, when parked the speeder will have to use an anchor of some kind or turn the vehicle off once on ground.

Ok so here is a list of GCP approaches Marc puts up and I've crossed out the ones which I think are either incorrect or unviable:

• Zero out gravity of the vehicle? 
• Zero out surrounding gravity?
• Antigravity?
• Force fields on space itself? Yes but depends on what is meant by "force fields" and "space" however this is the closest option which would agree with the model. Although the first two in the list regarding zeroing out gravity can be net effects they are incorrect because we cannot "zero out" the background accelerating virtual fermion field. Note that inertia is also not "zeroed out" in this process.
• Shield gravity?
• Ground repulsed?

The problem of providing a gravity earth-like environment in a starship (without relying on spinning structures or linear acceleration) can be reworded as: the flat spacetime metric inside the starship needs to be curved locally since gravity is curved spacetime. This is assuming the starship is in deep space, stopped and far away from a gravity well.

As far as keeping the artificial gravity net acceleration 1g inside the starship constant for the crew, the situation gets complicated if the starship is in orbit around a planet, undergoes manoeuvres ie accelerations, changes in altitude, course corrections etc. Speculating here, a super fast computer would have to evaluate the exterior spacetime metric curvature in real time and compensate the metric curvature inside the starship accordingly all this while taking into account the starship's own accelerations. It should be noted that there is no such thing as a pure flat spacetime metric anywhere in the Universe, however for discussion purposes far away from large masses it is a close approximation.

I haven't looked into this however it is quite feasible if the model allows one to change a curved spacetime metric to a flat metric then following symmetry principles in Physics, a flat spacetime can be curved artificially (not by using mass or energy-density as done by Nature). So in other words an acceleration needs to be imparted to the local virtual fermion particle field to obtain a net effect of curved spacetime which would result in local artificial gravity in the starship equivalent to natural gravity at ground level on Earth.

According to the model, Mach's Principle (and all the variants) is incorrect. Local physics is not determined by the large scale structure of the Universe. The large scale mass distribution of the Universe determines the widescale spacetime metric structure but within the spacetime metric inertia is purely a local quantum effect. The starship in the above slide is not pushing "against the mass of the Universe" but locally. As we'll see the model shows no inconsistencies with the Equivalence Principle which is an important test however other subtle problems are run into which will be explored in the upcoming paper I'm working on titled "A quantum model of spacetime metrics".

All in all an interesting talk by Marc, this is the last post on these GCP part series. The 100 Year Starship Symposium is coming up next month hopefully they'll have videos on the talks as well.

CI.

Ship spotting Sunday

Well after a few hours flattening spacetime metrics ;-) I went for a walk this early evening and spotted Carnival Spirit in Circular Quay. She's a decent size passenger ship, only departed half an hour or so later after I took the photo.

Carnival Spirit getting ready to depart Circular Quay. Photo: CI.

Comments on Starship Congress 2013

I hope that video streaming for future interstellar conferences will be standard as I suspect many people outside the US can't attend. Some comments which came to mind after watching the videos:

• Not much was said about the space radiation problem for humans (it is estimated a human can only survive up to 2 to 3 years in space in a standard spacecraft). This problem will have to be solved before long human deep space missions are considered. Otherwise probes will continue to do most exploring for us for the foreseeable future. Even a trip to Mars several months long poses a radiation health issue for the crew. The passive and active shield systems for the spacecraft will have to protect at least the human habitat in the spacecraft from dangerous space radiation and bring it down to at least 30mSv/year (workplace maximum radiation dose standard). At sea level, cosmic radiation exposure is 0.3mSv/year, at an altitude of 3Km it is 1.2mSv/year in Europe. There is a rundown on the problem discussed here. For any future manned interstellar mission (including deep solar system) this is a high priority research topic.

• As mentioned previously in this blog, it is unlikely interstellar travel will kickoff unless a replacement for chemical rockets is found to place hardware from ground to Low Earth Orbit. The expected large amount of hardware required for interstellar missions will make the cost too prohibitive. So although it is interesting to discuss interstellar missions which most likely won't happen for at least another 50-100 years, unless the more pressing problems are solved first, it is unlikely there will be interstellar missions for a very long time. Space Drives or Gravity Control Propulsion would be a game changer, this should be another high priority research topic. Even if a space elevator is built here on Earth, it doesn't solve the problem for Low Planetary Orbit to ground and vice versa transfers on other planets.

• Warp Drives and Wormholes: as mentioned previously these are allowed in General Relativity only but denied by Quantum Physics. Experiments related to these will continue to yield negative results. General Relativity is a classical model of the background dynamic quantum vacuum which works very well at describing Nature however the research so far hasn't shown how Quantum Physics would allow warp drives and wormholes to be physically possible.

CI. 

Update: There's an interesting wiki article as well on the space radiation issue worth a read: Health threat from cosmic rays.

Update: The Space Elevator Conference is on at the moment in Seattle. Last time I checked the state of the art fabrication process could only make carbon nano tube fibres a few centimetres long in the lab. These fibres need to be yarned into a cable long enough to reach geosynchronous orbit for the space elevator tether. A steel cable doesn't have enough tensile strength and at a length of 35786 Km will just break. Interesting to keep an eye where they are up to. To me this is Plan B if Space Drives or GCP turn out to be unviable because space elevators require a considerable amount of infrastructure to work while a hypothetical GCP enabled ship would not and would be free to manoeuvre around a planet (a big advantage). Also keep an eye out for the Skylon Project (Plan C), cargo transport is limited but the vehicle itself is quite neat and is really a big improvement over the Space Shuttle if they can get it working. The space elevator and the Skylon Project (not quite) are currently the only viable alternatives to chemical rockets regarding getting hardware into orbit from Earth that are feasible. 

Starship Congress 2013

Starship Congress 2013 is on at the moment in Dallas. There was an interesting talk by Marc Millis on Day 3 regarding Space Drives.

CI.

Is Gravity Control Propulsion viable? Part 5

Continuing on from the previous post with the EMQG model, we need to dissect the fermion family of virtual particles of the accelerating quantum vacuum and establish which virtual particles are contributing to spacetime curvature (gravity). More specifically, the interactions between the accelerating charged virtual fermion particles and the real fermion particles in a test mass is the result of the effect we perceive as gravity, we'll need to look at this in detail. Since there is interaction, not surprisingly real fermion particles can also influence the average motion of virtual fermion particles for a particular reference frame, we observe this as vacuum dragging effects mentioned in the previous post however these effects are much weaker than the gravitational effects due to the much lower mass of the virtual fermion particles, all this loosely translates from GR as spacetime tells mass how to move and mass tells spacetime how to curve. It is suspected that the cross section of real fermion particles in a test mass presented to the accelerating virtual particle field (spacetime) plays some part in this process together with the motion of quarks within nuclei and energy density.

For GCP to be useful for propulsion purposes, one aim is to be able to impart a 100% weight reduction on a test mass at ground level. Note from a GR point of view since gravity is curved spacetime, we need to give a certain volume a flat spacetime metric within a curved spacetime metric as shown below.

One aim for GCP is to be able to impart a flat spacetime metric around a test
mass within a curved spacetime gravity well. Images: CI.

The test mass of course needs to be totally enclosed in the flat spacetime volume. Another aim for GCP is to be able to move this imparted flat spacetime metric with the test mass within the gravity well (from ground to orbit for eg). Note from a GR point of view there is no difference in the metric far away from Earth's gravity well, the imparted flat spacetime metric within the gravity well or at the center of Earth taking an ideal spherical model of Earth and excluding gravitational influences from the Sun, Milky Way etc for discussion purposes. According to the modified EMQG model for this flat spacetime to happen in the gravity well there can be no interaction allowed between the test mass and the downward accelerated virtual fermion particle field (spacetime). So in summary for GCP to be viable there are two requirements that must be met from a GR point of view:

1. To be able to impart a flat spacetime metric around a test mass within a curved spacetime gravity well.
2. To be able to move this imparted flat spacetime metric with the test mass within a gravity well.

To be clear here we are not warping the spacetime metric to render it flat as it might be interpreted when looking at the graph, this has nothing to do with "Alcubierre's warp drive" which although appears viable when looked at within GR only has been shown in this paper for eg to be unviable when quantum effects are also taken into account. The net effect of the flat spacetime is not the result of any "warping" of the spacetime metric.

The good news for GCP in principle charged virtual fermion particles can be deflected via magnetic fields however the bad news is we cannot do so for neutral uncharged particles. If we look at the fermion class of particles below however we are in luck as the only family of fermion particles that are neutral are the neutrinos:

Fermion particles (anti-matter equivalent not shown have same mass but opposite electric charge).
Image: The Standard Model

Do we need to concern ourselves with the neutrinos? It appears no. Remembering we are dealing with virtual not real particles, the current accepted model specifies that the three family of real neutrinos have a tiny mass and are electrically neutral weakly interacting particles. The virtual neutrinos (yet to be confirmed) are expected to have an insignificant mass and appear not to be involved in the EMQG gravity process we are looking at. A large number of neutrinos come from our Sun and pass right through Earth without ever interacting with a single atom in it. The radioactive isotopes of calcium and potassium in the bones of a human body for eg emit some 400 neutrinos per second and travel throughout the Universe even if lightyears of lead were hypothetically laid in their path.

Since the electron neutrino, muon neutrino, tau neutrino and their anti-matter counterparts are the only virtual fermion particles that are electrically neutral and appear not to contribute to spacetime curvature (as per the modified EMQG model), the following is proposed:

All accelerating virtual fermion particles that contribute 
to gravity have a non-zero electric charge. 

We need to make a few remarks on virtual particles before we go on further, after all the model relies heavily on them. Virtual particles can be regarded as very short lived excitations of the background fluctuating quantum vacuum that can act as interaction mediators but don't quite have enough energy to become real particles themselves (however sometimes they do break free to become real particles if given enough energy). Their existence is so short lived they cannot be directly observed (hence the term virtual) however they make their presence known to us by various effects they cause to real particles which we can observe such as vacuum polarisation, Casimir effect, Hawking radiation, Lamb shift, spontaneous emission of photons, radioactive decay etc. They always come in pairs ie the virtual particle and its counterpart virtual anti-particle both with equal but opposite electric charge. The pair of virtual particles then annihilate giving back the energy borrowed from the quantum vacuum during their short lived existence. In some situations for eg in the presence of a strong electric field exceeding the critical value of \(E_{c}=\frac{m_{e}^{2}c^{3}}{e\hbar}=1.3EV/m\) (a prediction from the Dirac equation) or at a black hole event horizon via Hawking radiation, the virtual electron-positron pairs are prevented from recombining and the system pair is boosted by energy to become real electron and positron free particles. This "pair creation" process is the result of transformation of energy into matter via the quantum vacuum.

A visualisation of a virtual particle / anti-particle pair, not free particles hence called virtual.
Note that Nature does not allow us to distinguish or observe virtual particles. Image: unknown

Electric charge for virtual particles is conserved (otherwise the vacuum's net electric charge would not be neutral and there would be vacuum polarisation) and because of the Heisenberg indeterminacy relation for virtual particles we have \(\Delta E\Delta t < \frac{\hbar}{2}\) (for real particles \(\Delta E\Delta t\geq\frac{\hbar}{2}\) applies) ie in Nature:

Actions or changes smaller than \(\hbar=1.06\cdot10^{-34}Js\) cannot be observed. 

All of Quantum Physics comes from this simple statement, Nature's "behind the scene clockwork" is directly hidden to us behind \(\hbar\). Virtual particle mass also differs from their real particle counterparts which depends on how long in time they exist (the longer they exist, the less massive they can be and vice versa) and they do not obey the energy-momentum relation as real particles do ie for virtual particles \(E^{2}\neq m^{2}c^{2}+p^{2}c^{2}\) hence in some instances virtual particles can move faster than light (which real particles cannot) and since they are unobservable this doesn't contradict Special Relativity.

We need to look at next which accelerating charged virtual fermion particles are interacting with the nuclei (protons and neutrons) of a test mass to cause the effect we perceive as gravity. We can discount an interaction acting on the electron cloud surrounding nuclei for this effect. Most matter in the Universe is in the form of nuclei stripped bare of their electron cloud (ionized) for eg matter inside stars, cosmic rays, intergalactic matter mostly made of protons etc, your run in the mill atom with an electron cloud is not the most common form of matter in the Universe. On Earth we are somewhat shielded by an atmosphere and magnetic field that prevents most matter on its surface from being ionized. A neat experiment also settles the issue: Bouncing Neutrons in the Gravitational Field. It was shown in the experiment that slow neutrons bounced off a reflecting surface in a gravitational field alone like a ball bouncing off a table.

Bouncing neutrons in the gravitational field. Image: Scherer

It is interesting to note that the neutron states were found to be quantised which is expected however the experiment says nothing if the background gravitational field is quantised or not because no transition of a neutron between two states was observed, if it was, this would be a strong case for the graviton model and we can throw the modified EMQG model in the bin. Although neutrons are electrically neutral they do have a small magnetic moment since each neutron is made of charged quarks namely 1 up quark and 2 down quarks (udd or +2/3 -1/3 -1/3 = 0). A proton is made of 2 up quarks and 1 down quark (uud or +2/3 +2/3 -1/3 = +1).

So far the model can explain all of General Relativity but we still lack a detailed description of the interactions between the nuclei and the accelerated charged virtual fermion particle field, the model does explain photon behaviour in a gravitational field though. We need to look at how the virtual Quarks and Leptons interact with nuclei to explain GR effects on a test mass. We are getting into Quantum Chromodynamics here which is not straightforward physics especially since current QCD says nothing on the properties of spacetime and how it behaves in curved spacetime. As mentioned previously the EMQG model also does not explain the root cause of the downward acceleration of the virtual fermion particle field. It is suspected that the individual quark makeup of a nuclei isn't a major factor in the interaction involved but it is the motion of quarks within the nuclei that play a major role (as confirmed by GR it is any energy density that causes spacetime curvature). How the strong nuclear interactions for quarks within a nuclei with their exchange of virtual gluons that keep them together relates to the accelerated charged virtual fermion particle field is another area being looked at.

We will also need to demonstrate that suppressing the virtual fermion field around a test mass can indeed affect gravitational effects. Physics being an experimental science, some things cannot be worked out with pencil and paper alone, the experiment will need to be carried out to test this for a range of magnetic field intensities upto 100 Tesla (current state of the art). We can treat the virtual fermion particle field as a "virtual charged fluid" for all intents and purposes. Note that accelerated real charges produce a magnetic field, this is not observed for the virtual field case. A tightly collimated magnetic bottle should do the trick and we'll use a superconductor sphere to exclude the magnetic field which houses a test mass within.

A proposed experiment to test the modified EMQG model. A test mass is placed inside the spherical hollow superconductor. The magnetic bottle has to be tightly collimated at both extremeties. Circular vacuum polarisation is predicted to occur within the magnetic field envelope. Image: CI

The difficulty in the experiment will lie in how well the collimation at the extremeties can be achieved at the expected high magnetic field intensities. It is unlikely that this experiment would prevent all charged virtual fermion particles from interacting with the test mass inside the superconductor sphere, if this were to occur, according to the model, a 100% weight reduction will occur for the test mass. What we wish to happen here is a change of the nearly linear downward accelerated motion of the charged virtual fermion particle field to a circular one. The net effect of this is the same as having a flat spacetime metric within a curved gravity well as mentioned previously. Note that looking at the side view of the envelope, the magnetic field can be made to go into or out of the screen with the same result for the test mass.

We'll leave the finer technicalities of this model for a paper currently being worked on. The challenging part of this model is to come up with viable physics for the interaction of nuclei with charged virtual fermions which doesn't contradict known working physics models.

Answering the original question which started these post series is Gravity Control Propulsion viable? At this stage the answer is still no. If the model doesn't end up in the bin and shows some promising results, maybe.

CI.

Star size comparaisons

Interesting video on APOD here

Is Gravity Control Propulsion viable? Part 4

From the previous post, we'll follow on from  the general idea of an accelerating quantum vacuum composed of virtual particles interacting with mass which we perceive as gravity (spacetime curvature) and responsible for weight emphasising that this is only a hypothesis that appears to fit General Relativity and may provide an avenue to make new testable quantum predictions on gravity. We haven't ruled out the other possibilites though which are graviton exchange between mass, a combination of quantum vacuum electromagnetic interactions and gravitons, or other interactions via unknown particles. As noted in the previous post, the graviton hypothesis is not a testable model for the foreseeable future and cannot be proved or disproved by experiment so can't be ruled out although is not helpful for our aim for Gravity Control Propulsion (GCP) since we have no control of graviton interactions. We will also look at Gravitoelectromagnetism (vacuum dragging effects). Although there are similarities between Maxwell's field equations and the GR field equations, we'll show later that it appears this cannot be used for GCP. Both classical electromagnetism and gravity operate under Gauss's inverse square law in a three dimensional space, this is where the similarities end, however gravitoelectromagnetism is a useful tool to model the effects of gravity under certain circumstances (such as gravitational waves). Our main aim is to investigate if there is any direct relation between electromagnetism and gravity and understand Nature's mechanism for spacetime curvature due to mass and energy density. Since we are good at manipulating experiments that are electromagnetic based, if there is a relation there would be avenue for GCP related experiments down the track. If there is no relation between electromagnetism and gravity, GCP is in trouble.

The accelerating quantum vacuum is composed of the full spectrum of virtual particles which have their counterpart real particles. Among them there are virtual electrons and positrons (part of the lepton family of particles) both of which have electric charge which means there is avenue for interaction via electromagnetism. We will also need to look at the mix of virtual particles that have zero charge. The diagram below shows the situation quite well for a particle with charge q, velocity v, and the effect of the Lorentz force on this test charge (negative, positive or neutral) due to a magnetic field B coming out of the screen perpendicular to you.



Deflection of a test charge q due to a magnetic field coming out of the screen. Image: Wikipedia.



 Let's have a look at another paper that proposes a similar hypothesis to the previous paper: Does the Quantum Vacuum Fall Near the Earth? The Downward Acceleration of the Quantum Vacuum is Responsible for the Equivalence Principle.

This paper makes several modifications to the previous accelerating quantum vacuum model and although it makes several interesting points it also introduces some highly speculative propositions. In summary the paper proposes:

The downward acceleration of the virtual electrically charged fermion particles of the quantum vacuum is responsible for the Einstein Weak Equivalence Principle and for our perception of 4D space-time curvature near the earth. Since the virtual fermion particles of the quantum vacuum (virtual electrons for example) possess mass, we assume that during their short lifetimes the virtual fermions are in a state of downward acceleration (or free-fall) near the earth. Many of the virtual fermions also possess electrical charge, and are thus capable of interacting electrically with a real test mass, since a test mass is composed of real, electrically charged, fermion particles. The electrical interaction between the downward accelerated virtual fermions with nearby light or matter is responsible for the equivalence of inertial and gravitational mass, and also responsible for our perception of 4D space-time curvature near the earth.

The opposition to acceleration of a test mass by the reverse process is explained to be the cause of inertia. Key point here that is of interest to us is where it is mentioned that the virtual fermions are interacting electrically with mass. It remains to be seen if this hypothesis (ElectroMagnetic Quantum Gravity or EMQG) is correct and if this is the only cause of gravity. The paper does not give a mechanism for the root cause of the downward acceleration of the quantum vacuum however the concept as outlined is enough to explain GR and vacuum dragging effects which is why the model is interesting. We are also moving on from the classical explanation of GR to a quantum model of gravity:

 4D curved Minkowski space-time is now a consequence of the behavior of matter (particles) and energy (photons) under the influence of this (statistical average) downward accelerated ‘flow’ of charged virtual particles of the quantum vacuum. This coordinated ‘accelerated flow’ of the virtual particles can be thought of as a special ‘Fizeau-like vacuum fluid’ that ‘flows’ through all matter near a gravitational field (and also in matter undergoing accelerated motion). Like in the Fizeau experiment (which was performed with a constant velocity water flow) the behavior of photons, clocks, and rulers are now affected by the downward accelerated flow of the virtual particles of the quantum vacuum caused by gravity.

We'll note that the vacuum's net electric charge is neutral and there must be equal numbers of virtual electrons and virtual positrons (anti-electrons) at a given time due to pair creation and annihilation processes. Since these two particles have equal and opposite electrical charge they both react to magnetic fields. Also since this "Fizeau-like vacuum fluid" of virtual particles interacts with normal matter, we can deduce that motion of matter can also influence this "vacuum fluid" which we observe as vacuum dragging effects (gravitomagnetism), normal matter being made of protons and neutrons which are made of charged quarks with our usual cloud of charged electrons surrounding the nucleaus for a standard atom. Also note that this is not a Superfluid Vacuum Theory or Aether model although there are some similarities. 

Real electron and positron curl in opposite directions in a bubble chamber magnetic field. Image:  Britannica

On p8 the paper talks about Hawking radiation for black holes which is of interest to us because here is a special case where the virtual particle and anti-particle pairs do not undergo annihilation at the event horizon and offers further insight on the physics of the quantum vacuum virtual particle field. Vacuum polarisation also shows that our observations of real electron charge is affected by the cloud of virtual positrons of the quantum vacuum that congregate around the electron (also known as charge screening). On p11 the paper goes on to explaim the EMQG model of gravity involving two particle exchange mechanisms:

What is unique about EMQG theory is that gravitation involves both the photon and graviton exchange particles operating at the same time, where now the photon plays a very important role in gravity! In fact, the photon exchange process dominates over the pure gravitational interaction, and is in the most part, responsible for the principle of equivalence of inertial and gravitational mass. The photon particle is also responsible for another property that all matter possesses, the inertial force that acts to give a mass the property of Newtonian inertia.

We cannot verify part of the claim that gravitation involves graviton exchange particles as explained previously (although this is the current accepted norm in Physics) however we can verify photon exchange mechanism in principle. It is mentioned on p13 that there appears to be a deep connection between electromagnetism and gravity because Coulomb's electrical force law: \(F=\frac{KQ_{1}Q_{2}}{r^{2}}\) and Newtonian gravitational force law: \(F=\frac{GM_{1}M_{2}}{r^{2}}\) are similar. Both classical electromagnetism and gravity operate in a three dimensional space where Gauss's inverse square law is applicable. Gravitomagnetism was devised well before GR as a tool to model gravity using the similarities between the two forces. Gravitational waves for eg can be modeled by splitting the gravitomagnetic and gravitoelectric components just like electromagnetic waves can be split into their electric and magnetic field vector components. It appears that no further insight will be gained with this approach since this is a classical tool devised for a classical model of gravity although useful to explain vacuum dragging effects and gravitational waves. We'll keep it as a set for our classical toolbox though. Attempts to discover direct mechanisms to convert electromagnetism to gravity based on the gravitoelectromagnetic field equations are expected to be unsuccessful (see for eg Coupling of Gravitation and Electromagnetism in the Weak Field Approximation).    

Examples of vacuum dragging: Thirring and Thirring-Lense effects. Image: Motion Mountain, Vol 2, p150

On p14 interesting questions are put forward:

Does the graviton particle move in a 4D flat space-time like the photon of QED? Does the graviton exchange process somehow ‘produce’ curvature on an otherwise flat background 4D space-time, when propagating from one mass to another? If the graviton is not responsible, then what is it about mass that is directly capable of producing 4D space-time curvature surrounding the mass? In other words, if the 4D space-time curvature is not caused by the graviton exchanges, then what is the connection between matter and 4D space-time? If you double the mass, you change the amount of space-time curvature. Why?

To our knowledge, these questions remain unanswered. In EMQG, we propose a quantum action based on the quantum vacuum and the existence of graviton particles (that have characteristics very similar to the photon) that resolves these questions. It turns out that the state of acceleration of the quantum vacuum with respect to another test mass represents the quantity of 4D space-time curvature!

 The concept of an accelerating quantum vacuum responsible for 4D spacetime curvature is plausible and also can explain vacuum dragging effects. We will look at some of the problems with the model though and possible modifications required without resorting to new particles (such as the paper's "masseon" particle). Although EMQG also resorts to gravitons for part of their explanation for 4D curvature, it is not clear at this stage if this is a requirement for a successful model since we are unable to question Nature if she is actually using gravitons to mediate gravity. It should be noted that from p16 regarding a derivation for GR, there is a relatively straightforward derivation offered in Motion Mountain Vol 2 Ch 4 "Simple General Relativity: Gravitation, maximum speed and maximum force". Just like Special Relativity is based on maximum speed c in Nature, GR can be derived from the following: There is in Nature a maximum force: \(F\leq\frac{c^{4}}{4G}=3.0\cdot10^{43}N.\) Both maximum speed c and maximum force are properties of the vacuum. It is interesting to note here from Motion Mountain Vol 2 p33:

However, there is at least one system in nature where the speed of sound is indeed a limit speed for energy: the speed of sound is the limit speed for the motion of dislocations in crystalline solids. (We discuss this in detail later on). As a result, the theory of special relativity is also valid for dislocations, provided that the speed of light is replaced everywhere by the speed of sound! Indeed, dislocations obey the Lorentz transformations, show length contraction, and obey the famous energy formula \(E=\gamma mc^{2}\). In all these effects the speed of sound c plays the same role for dislocations as the speed of light plays for general physical systems.

The observation above is interesting for the model of the accelerating quantum vacuum which we are looking at. On p 35, the paper asks the important questions:

Does the general downward acceleration of the virtual particles of the quantum vacuum near a large mass affect the motion of photons propagating within the gravitational field? Or is the deflection of photons truly the result of an actual spacetime geometric curvature (which holds down to the tiniest of distance scales)? 

The answer to this very important question hinges on whether our universe is truly a curved, geometric Minkowski 4D space-time on the smallest of distance scales, or whether curved 4D space-time results merely from the activities of quantum vacuum virtual particles interacting with other real quantum particles. EMQG takes the second view. 

According to postulate 4 (appendix A-11) of EMQG theory, light takes on the same general acceleration as the net statistical average value of quantum vacuum virtual particles, through a ‘Fizeau-like’ scattering process involving many virtual particles. By this we mean that the photons are frequently absorbed and re-emitted by the electrically charged virtual particles, which are (on the average) accelerating towards the center of the large mass. When a virtual particle absorbs the real photon, a new photon is re-emitted after a small time delay in the same general direction as the original photon. This process is called photon scattering (figure 5). We will see that photon scattering is central to the understanding of space-time curvature.

The second view looks plausible however the EMQG model as proposed in the paper with its introduction of several new hypothetical particles other than gravitons to explain how gravity is mediated is highly speculative and doesn't appear to be correct. We'll keep this aside for the time and make a mental note that this part of the model still needs work. The explanation from p39 on photon scattering in a static and accelerated quantum vacuum is interesting. It is feasible that the photon undergoes a time delay between absorption and re-emission between each charged virtual particle it encounters in the quantum vacuum and undergoes a "photon vacuum delay" which gives an average light velocity of 300000 Km/s. It is not clear however if there is a higher "raw light velocity" of the photon between each charged virtual particle, at this stage this cannot be verified (however see the following paper: Does the speed of light depend upon the vacuum?). One can speculate if the density of the charged virtual particles could be reduced somehow in a given volume of the quantum vacuum, this average light velocity could be increased as the number of encounters with charged virtual particles is decreased. The charged virtual particles can be seen as offering resistance to the propagation of the photons. This fits in well with photon scattering processes in materials, Fizeau's moving water experiment mentioned earlier in the paper and the equations of motion of dislocations in crystalline solids mentioned above.  We'll follow on from p44:

We are now in a position to understand the concept of the geodesic proposed by Einstein. The downward acceleration of the virtual electrically charged masseons of the quantum vacuum serves as an effective ‘electromagnetic guide’ for the motion of light (and for test masses) through space and time. This ‘electromagnetic guide’ concept replaces the 4D space-time geodesics that guide matter in motion in relativity. For light, this guiding action is through the electromagnetic scattering process of section 9.5. For matter, the electrically charged virtual particles guide the particles of a mass by the electromagnetic force interaction that results from the relative acceleration. Because the quantum vacuum virtual particle density is quite high, but not infinite (at least about \(10^{90}\) particles \(/m^{3}\), the quantum vacuum acts as a very effective reservoir of energy to guide the motion of light or matter.

If the overall model turns out to be correct and we can devise a method to interfere with the electrical interaction of the vast numbers of falling virtual charged particles with the real, electrically charged matter particles for a test mass then there is an avenue to carry out GCP related experiments. What is interesting here is that although the details in the gravity mediation process is still unclear at this stage, the effect isn't and if the  secondary cause is via electrical interactions we can in principle interact or interfere with the process even if the root cause turns out to be via neutral gravitons which we cannot interact or modify.

At this stage however using the above model (if correct) we can for example rule out the Podkletnov and Tajmar experiments which both rely on rotating superconducting rings. Podkletnov's experiment claimed a 2% weight reduction on a test mass in the center of the ring. The magnetic field generated by the rotating superconducting ring is not preventing the accelerating quantum vacuum charged virtual particles from interacting with the test mass at its center as the field configuration in incorrect. Another experiment by Tajmar was devised to look at gravitomagnetic and gravitoelectric fields is also incorrect. As mentioned previously above, one should not confuse vacuum dragging effects that can be modeled with classical gravitomagnetism with actual real fields in Nature.

Podkletnov's experiment: no weight reduction can be obtained with this configuration.  

Tajmar's experiment: no gravitoelectric and gravitomagnetic fields can be found,
only vacuum dragging effects can be measured.

In Part 5 of these series, we'll look at some of the problems with the EMQG model and modifications required that doesn't rely on hypothetical particles. We also need to deal with the neutral virtual particles that make up the accelerating quantum vacuum and look at some testable predictions that can be verified by experiment.

CI.

Update: Interesting post on Backreaction: Quantum gravity phenomenology detecting gravitons