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Special relativity predicts a very small influence of temperature on mass of around ${\Delta}m/m{\approx}10^{-14}$. More than 100 years ago, experiments were performed that revealed a limit of $<10^{-8}$ for changes of a few degree at room temperature. A similar limit was obtained with a magnetic suspension balance at cryogenic temperatures. Recently, some measurements claim to have seen a negative dependence at the $10^{-6}$ level for a variety of metal samples at room temperature, which would be of interest e.g. to explain variations in the measurement of the gravitational constant. We have performed measurements with an analytical balance in vacuum and with a commercial thermogravimetric balance in argon and obtained a $3{\sigma}$ limit of $<1.8 \times 10^{-8}$ for both metallic (Cu, Pt) and non-metallic (Al2O3) samples ranging from room temperature to above $1000{\deg}C$. This extends previous measurements to the high-temperature regime and rules out all claimed anomalies by more than two orders of magnitude.

According to Weber's electrodynamics, Assis showed analytically, that a field-free electrostatic potential delivered by a spherical shell causes a force upon a moving electrical charge in the center of that shell. This force can be interpreted as a result of the change in inertial mass of the charge. In order to prove this theory, Mikhailov published two type of experimental setups: One using vacuum cathode tube and another using glow-discharge-lamps to generate oscillating and accelerating electrons. Whereas the glow-discharge experiment was already evaluated by several groups, here we are focusing on replicating the vacuum tube configuration. Under right circumstances, electrons inside a vacuum tube start to oscillate around a grid electrode, which is called Barkhausen-Kurz oscillations. However, we found that Mikhailov's setup does not produce these kind of oscillations and therefore the theory that he applied in the interpretation of his measurements is not correct. We succeeded in generating Barkhausen-Kurz oscillations with a different vacuum tube and found no frequency shifts below an order of magnitude of Assis's prediction by operating the tube inside a charged spherical shell that would indicate a change in the electron's mass. However, since both the mass as well as the geometry factor of the electron cloud contribute to the oscillator frequency, we believe that this setup is not suitable to investigate Weber-type electrodynamic effects.

In the year 2002 publications of A.V.M. Khachatourian and A.O. Wistrom were released, in which the existence of an electrostatic torque has been claimed. This moment of force should act in a three sphere configuration, where one sphere is held at a constant electric potential. This claim was based on an observed rotation and was supported by a mathematical solution derived by Wistrom and Khachatourian. The theoretical work of Wistrom and Khachatourian as well as the interpretation of the observed rotation were criticized by several scientists who offered alternative explanations for the rotation. We therefore designed an experimental setup which enabled us to investigate the phenomenon. By performing numerous measurements, we showed that the rotation is due to asymmetric mass distribution within the sphere, which is dislocated due to electrostatic forces between the spheres. We were able to clear our measurements from this effect and observed a null result more than two orders of magnitude smaller than predicted by Khachatourian and Wistrom's theory. We therefore showed that the rotation doesn't occur in an electrostatic system within the resolution of our experiment., Comment: Accepted for publication in Journal of Electrostatics

A number of weight anomalies have been reported in the past with respect to gyroscopes. Much attention was gained from a paper in Physical Review Letters, when Japanese scientists announced that a gyroscope loses weight up to $0.005\%$ when spinning only in the clockwise rotation with the gyroscope's axis in the vertical direction. Immediately afterwards, a number of other teams tried to replicate the effect, obtaining a null result. It was suggested that the reported effect by the Japanese was probably due to a vibration artifact, however, no final conclusion on the real cause has been obtained. We decided to build a dedicated high precision setup to test weight anomalies of spinning gyroscopes in various configurations. A number of error sources like precession and vibration and the nature of their influence on the measurements have been clearly identified, which led to the conclusive explanation of the conflicting reports. We found no anomaly within $\Delta m/m<2.6 \times 10^{-6}$ valid for both horizontal and vertical orientations., Comment: Accepted for publication in Measurement

We show that the Casimir effect should be influenced by variations of the gravitational potential. This could be tested with a satellite in a highly elliptic orbit. Still significant technology development is required to achieve a relative accuracy of $<5 \times 10^{-10}$ necessary to detect the effect around Earth. That may be obtained in the future based on recent concepts for giant casimir forces. Such a space mission could evaluate both the laws of gravitation and quantum mechanics and their interaction. A dedicated mission, Gravity-Probe C, is proposed.

The Planck units were originally derived from a dimensional analysis without a deeper understanding of their meaning. It was later believed that these units may provide a link between quantum theory and gravity in a yet to be developed theory of quantum gravity. I propose a model where the Planck units appear naturally by assuming that the quantum vacuum can be gravitationally polarized based on recent work on the gravitational properties of anti-particles. In order to match the observed values, we arrive at Planck particle/anti-particle pairs (micro black holes) with Planck masses that define the gravitational constant in vacuum through gravitational polarization. This gives the Planck mass a new important interpretation as indeed linking quantum fluctuations to gravity by defining the gravitational constant. In addition, a better understanding of why the Planck length is usually associated as the smallest length in nature can be illustrated from another perspective., Comment: To appear in Physics Essays Vol 25(3), 2012

We previously reported anomalous fiber-optic gyroscope signals observed above rotating rings at temperatures close to liquid helium. Our results suggested that the liquid helium itself may be the source of our observed phenomenon. We constructed a new cryostat experiment that allows rotating a large quantity of liquid helium together with a superconducting niobium tube. The facility is built in such a way that our gyroscope can be placed directly in the center of rotation along the axis; however, the cryostat is built around the gyroscope to allow measuring without interference of helium liquid or gas. An anomalous signal was found of similar value compared to our previous measurements with a changed sign. As this measurement was done at a different location (center position) with respect to our old setup (top position), first hints for a possible field distribution of this phenomenon can be made. However, due to lower angular velocities used in this new setup so far, our measurement resolution was close to three times the resolution of our gyroscope and hence our data represent work in progress., Comment: To appear in the SPESIF-2010 conference proceedings published by AIP

Precision fiber optic gyroscopes were mounted mechanically de-coupled above spinning rings inside a cryostat. Below a critical temperature (typically <30 K), the gyroscopes measure a significant deviation from their usual offset due to Earth's rotation. This deviation is proportional to the applied angular ring velocity with maximum signals towards lower temperatures. The anomalous gyroscope signal is about 8 orders of magnitude smaller then the applied angular ring velocity, compensating about one third of the Earth rotation offset at an angular top speed of 420 rad/s. Moreover, our data shows a parity violation as the effect appears to be dominant for rotation against the Earth's spin. No systematic effect was found to explain this effect including the magnetic environment, vibration and helium gas friction suggesting that our observation is a new low temperature phenomenon. Tests in various configurations suggest that the rotating low temperature helium may be the source of our anomalous signals., Comment: Poster presented at the 25th Low Temperature Physics Conference, Amsterdam, Aug 2008, to appear in the Journal of Physics Conference Proceedings

An extension to the model from Berger is proposed to analyse the nonlinearity of the magnetic field from a rotating superconducting shell, taking into account the effect of the London penetration depth.

A fully consistent model to study electrodynamics for superconductors in the stationary and non-stationary regime has been developed based on Proca equations and a massive photon. In particular, this approach has been applied to study the electric field penetration depth in superconductors. The model shows a deviation from the charge contribution to an internal electric field compared to previous approaches., Comment: Accepted for publication in Phys. Lett. A

High-resolution accelerometer and laser gyroscope measurements were performed in the vicinity of spinning rings at cryogenic temperatures. After passing a critical temperature, which does not coincide with the material's superconducting temperature, the angular acceleration and angular velocity applied to the rotating ring could be seen on the sensors although they are mechanically de-coupled. A parity violation was observed for the laser gyroscope measurements such that the effect was greatly pronounced in the clockwise-direction only. The experiments seem to compare well with recent independent tests obtained by the Canterbury Ring Laser Group and the Gravity-Probe B satellite. All systematic effects analyzed so far are at least 3 orders of magnitude below the observed phenomenon. The available experimental data indicates that the fields scale similar to classical frame-dragging fields. A number of theories that predicted large frame-dragging fields around spinning superconductors can be ruled out by up to 4 orders of magnitude., Comment: Paper presented at the 18th International Conference on General Relativity & Gravitation, Sydney, Jul 2007 and at the Time & Matter Conference, Bled, Sept 2007, GPB Data Corrected and Model Updated

It is well known that a rotating superconductor produces a magnetic field proportional to its angular velocity. The authors conjectured earlier, that in addition to this so-called London moment, also a large gravitomagnetic field should appear to explain an apparent mass increase of Niobium Cooper-pairs. A similar field is predicted from Einstein's general relativity theory and the presently observed amount of dark energy in the universe. An experimental facility was designed and built to measure small acceleration fields as well as gravitomagnetic fields in the vicinity of a fast rotating and accelerating superconductor in order to detect this so-called gravitomagnetic London moment. This paper summarizes the efforts and results that have been obtained so far. Measurements with Niobium superconductors indeed show first signs which appear to be within a factor of 2 of our theoretical prediction. Possible error sources as well as the experimental difficulties are reviewed and discussed. If the gravitomagnetic London moment indeed exists, acceleration fields could be produced in a laboratory environment., Comment: To appear in the proceedings of the STAIF-2007 conference published by AIP

Superconductors have often been used to claim gravitational anomalies in the context of breakthrough propulsion. The experiments could not be reproduced by others up to now, and the theories were either shown to be wrong or are often based on difficult to prove assumptions. We will show that superconductors indeed could be used to produce non-classical gravitational fields, based on the established disagreement between theoretical prediction and measured Cooper-pair mass in Niobium. Tate et al failed to measure the Cooper-pair mass in Niobium as predicted by quantum theory. This has been discussed in the literature without any apparent solution. Based on the work from DeWitt to include gravitomagnetism in the canonical momentum of Cooper-pairs, the authors published a number of papers discussing a possibly involved gravitomagnetic field in rotating superconductors to solve Tate's measured anomaly. Although one possibility to match Tate's measurement, a number of reasons were developed by the authors over the last years to show that the gravitomagnetic field in a rotating quantum material must be different from its classical value and that Tate's result is actually the first experimental sign for it. This paper reviews the latest theoretical approaches to solve the Tate Cooper-pair anomaly based on gravitomagnetic fields in rotating superconductors.

It has been suggested that the Dark Energy Coincidence Problem could be interpreted as a possible link between the cosmological constant and a massive graviton. We show that by using that link and models for the graviton mass a dark energy density can be obtained that is indeed very close to measurements by WMAP. As a consequence of the models, the cosmological constant was found to depend on the density of matter. A brief outline of the cosmological consequences such as the effect on the black hole solution is given.

It is well known that a rotating superconductor produces a magnetic field proportional to its angular velocity. The authors conjectured earlier, that in addition to this so-called London moment, also a large gravitomagnetic field should appear to explain an apparent mass increase of Niobium Cooper-pairs. This phenomenon was indeed observed and induced acceleration fields outside the superconductor in the order of about 10^-4 g were found. The field appears to be directly proportional to the applied angular acceleration of the superconductor following our theoretical motivations. If confirmed, a gravitomagnetic field of measurable magnitude was produced for the first time in a laboratory environment. These results may open up a new experimental window on testing general relativity and its consequences using coherent matter., Comment: Submitted to Physica C

We show that non-zero masses for a spin-1 graviton (called graviphoton) leads to considerable gravitomagnetic fields around rotating mass densities, which are not observed. The solution to the problem is found by an equivalent graviphoton mass which depends on the local mass density to ensure the principle of equivalence. This solution, derived from Einstein-Proca equations, has important consequences such as a correction term for the Cooper-pair mass anomaly reported by Tate among many others. Similar results were obtained for the photon mass which is then proportional to the charge density in matter. For the case of coherent matter the predicted effects have been experimentally observed by the authors., Comment: Signs corrected, updating of text, concentrate only on spin-1 graviphoton discussion

In nearly all concepts invoked or proposed to change or shield gravity it is intuitively assumed that manipulation of gravity automatically leads to a breakthrough for propulsion. In this study it is shown, that even if gravity could be hypothetically controlled along the manipulation schemes outlined, the gains in terms of propulsion would be modest and lead to no breakthrough. Although the manipulation schemes presented are not exhaustive, they include the most straightforward ones from the current physics point of view.

This paper has been withdrawn by the authors due to the inconsistency of the computations used for extra dimensions and the fractal dimensional approach of the paper. An updated version of the paper will be published under a different title.

Starting from the generalised London equations, which include a gravitomagnetic term, the gravitational and the electromagnetic properties of superconductors are derived. A phenomenological synthesis of those properties is proposed., Comment: gravitomagnetism, superconductivity, generalised London equations, generalised London moment, electromagnetism, inertia, gravity, Schiff-Barnhill effect

Applying the Ginzburg-Landau theory including frame dragging effects to the case of a rotating superconductor, we were able to express the absolute value of the gravitomagnetic field involved to explain the Cooper pair mass anomaly previously reported by Tate. Although our analysis predicts large gravitomagnetic fields originated by superconductive gyroscopes, those should not affect the measurement of the Earth gravitomagnetic field by the Gravity Probe-B satellite. However, the hypothesis might be well suited to explain a mechanical momentum exchange phenomena reported for superfluid helium. As a possible explanation for those abnormally large gravitomagnetic fields in quantum materials, the reduced speed of light (and gravity) that was found in the case of Bose-Einstein condensates is analysed.

A 3D finite-element numerical simulation was developed to investigate Casimir forces in arbitrary geometries. The code was verified comparing it with results obtained from analytical equations. Appling the simulation to previously not assessed configurations, new Casimir properties were found such as repulsive Casimir forces in groove like structures.

There have been a number of claims in the literature about gravity shielding effects of superconductors and more recently on the weight reduction of superconductors passing through their critical temperature. We report several experiments to test the weight of superconductors under various conditions. First, we report tests on the weight of YBCO and BSCCO high temperature superconductors passing through their critical temperature. No anomaly was found within the equipment accuracy ruling out claimed anomalies by Rounds and Reiss. Our experiments extend the accuracy of previous measurements by two orders of magnitude. In addition, for the first time, the weight of a rotating YBCO superconductor was measured. Also in this case, no weight anomaly could be seen within the accuracy of the equipment used. In addition, also weight measurements of a BSCCO superconductor subjected to extremely-low-frequency (ELF) radiation have been done to test a claim of weight reduction under these conditions by De Aquino, and again, no unusual behavior was found. These measurements put new important boundaries on any inertial effect connected with superconductivity - and consequently on possible space related applications., Comment: Version as appeared in the STAIF conference proceedings. Received Best Paper Award

A scientific analysis of the conditions under which gravity could be controlled and the implications that an hypothetical manipulation of gravity would have for known schemes of space propulsion have been the scope of a recent study carried out for the European Space Agency. The underlying fundamental physical principles of known theories of gravity were analysed and shown that even if gravity could be modified it would bring somewhat modest gains in terms of launching of spacecraft and no breakthrough for space propulsion., Comment: 5 pages, plain Latex

The quantization of the extended canonical momentum in quantum materials including the effects of gravitational drag is applied successively to the case of a multiply connected rotating superconductor and superfluid. Experiments carried out on rotating superconductors, based on the quantization of the magnetic flux in rotating superconductors, lead to a disagreement with the theoretical predictions derived from the quantization of a canonical momentum without any gravitomagnetic term. To what extent can these discrepancies be attributed to the additional gravitomagnetic term of the extended canonical momentum? This is an open and important question. For the case of multiply connected rotating neutral superfluids, gravitational drag effects derived from rotating superconductor data appear to be hidden in the noise of present experiments according to a first rough analysis.

The gravitational Poynting vector provides a mechanism for the transfer of gravitational energy to a system of falling objects. In the following we will show that the gravitational poynting vector together with the electromagnetic Poynting vector provides a mechanism to explain how massive electrically charged bodies acquire kinetic energy during a free fall. We will demontrate that falling electrically charged masses violate the Galilean law of universal free fall. An experiment is suggested to confirm or not the predicted phenomena.

The gravitational Poynting vector provides a mechanism for the transfer of gravitational energy to a system of falling objects. In the following we will show that the gravitational poynting vector together with the gravitational Larmor theorem also provides a mechanism to explain how massive bodies acquire rotational kinetic energy when external mechanical forces are applied on them.

One obtains a Maxwell-like structure of gravitation by applying the weak-field approximation to the well accepted theory of general relativity or by extending Newton's laws to time-dependent systems. This splits gravity in two parts, namely a gravitoelectric and gravitomagnetic (or cogravitational) one. Due to the obtained similar structure between gravitation and electromagnetism, one can express one field by the other one using a coupling constant depending on the mass to charge ratio of the field source. Calculations of induced gravitational fields using state-of-the-art fusion plasmas reach only accelerator threshold values for laboratory testing. Possible amplification mechanisms are mentioned in the literature and need to be explored. The possibility of using the principle of equivalence in the weak field approximation to induce non-Newtonian gravitational fields and the influence of electric charge on the free fall of bodies are also investigated, leading to some additional experimental recommendations.

Using the linearized theory of general relativity, the gravitomagnetic analogue of the Barnett effect is derived. Further theoretical and experimental investigation is recommended, due to the expected macroscopic values of the gravitomagnetic field involved in this effect, and to the constraints which would appear on quantum theories of gravity, currently under development, in case of non detection of the predicted phenomena., Comment: 10 pages, 1 figure

The theory of General Relativity explaines the advance of Mercury perihelion using space curvature and the Schwartzschild metric. We demonstrate that this phenomena can also be interpreted due to the cogravitational field produced by the apparent motion of the Sun around Mercury giving exactly the same estimate as derived from the Schwartzschild metric in general relativity theory. This is a surprising result because the estimate from both theoretical approaches match exactly the measured value. The discussion and implications of this result is out of the scope of the present work., Comment: 13 pages

Using the weak field approximation, we can express the theory of general relativity in a Maxwell-type structure comparable to electromagnetism. We find that every electromagnetic field is coupled to a gravitoelectric and gravitomagnetic field. Acknowledging the fact that both fields originate from the same source, the particle, we can express the magnetic and electric field through their gravitational respective analogues using the proportionality coefficient k. This coefficient depends on the ratio of mass and charge and the ratio between the electromagnetic and gravitic-gravitomagnetic permittivity and permeability respectively. Although the coefficient is very small, the fact that electromagnetic fields in material media can be used to generate gravitational and gravitomagnetic fields and vice versa is not commonly known. We find that the coupling coefficient can be increased by massive ion currents, electron and nuclear spin-alignment. Advances in material sciences, cryogenic technology and high frequency electromagnetic fields in material media may lead to applications of the derived relationships., Comment: This work does not reflect the opinion of any official institution