Electromagnetic Tensor Research Articles

Electrodynamics on cosmological scales

Maxwell's equations cannot describe a homogeneous and isotropic universe with a uniformly distributed net charge, because the electromagnetic field tensor in such a universe must be vanishing everywhere. For a closed universe with a nonzero net charge, Maxwell's equations always fail regardless of the spacetime symmetry and the charge distribution. The two paradoxes indicate that Maxwell's equations need be modified to be applicable to the universe as a whole. We consider two types of modified Maxwell equations, both can address the paradoxes. One is the Proca-type equation which contains a photon mass term. This type of electromagnetic field equations can naturally arise from spontaneous symmetry breaking and the Higgs mechanism in quantum field theory, where photons acquire a mass by eating massless Goldstone bosons. However, photons loose their mass when symmetry is restored, and the paradoxes reappear. The other type of modified Maxwell equations, which are more attractive in our opinions, contain a term with the electromagnetic potential vector coupled to the spacetime curvature tensor. This type of electromagnetic field equations do not introduce a new dimensional parameter and return to Maxwell's equations in a flat or Ricci-flat spacetime. We show that the curvature-coupled term can naturally arise from the ambiguity in extending Maxwell's equations from a flat spacetime to a curved spacetime through the minimal substitution rule. Some consequences of the modified Maxwell equations are investigated. The results show that for reasonable parameters the modification does not affect existing experiments and observations. However, the field equations with a curvature-coupled term can be testable in astrophysical environments where mass density is high or the gravity of electromagnetic radiation plays a dominant role in dynamics, e.g., interior of neutron stars and the early universe.

Modified Palatini action that gives the Einstein-Maxwell theory

The actions for bosonic fields typically contain terms quadratic in the derivatives of the fields. This is not the case in the Palatini approach to general relativity. The action does not contain any derivatives of the metric and it only contains terms linear in the derivatives of the connection. In general relativity the covariant derivative of the metric vanishes, so it is not possible to include such terms in the action. However, in more general theories this is not the case. In this paper I consider an action which is quadratic in the derivatives of the metric and connection and show that it leads to the coupled Einstein-Maxwell theory or the coupled Einstein-Proca theory with the antisymmetric part of the Ricci tensor playing the role of the electromagnetic field strength.

Cell Motility and Growth Factors According to Differentially Variational Surfaces

Fluid dynamics can be treated, as a motion of an inviscid fluid as an indivisible media of particles, or as a collective motion of many body system particles. First case leads to Euler equation of hydrodynamics or more complete Navier-Stokes equations. There are two possibilities of dealing with second case, treat each separate particles as an individual one and propose that each particle satisfies Newton's laws of motion rewritten in stochastic form (Langevin dynamics), or treat each particle as a vertex of geometric figure and search for equations of motion of such surfaces. The surfaces shall be called a differentially variational surfaces (DVS). We had proposed equations of motion of moving surfaces in electromagnetic field, on previous annual meeting, and applied it to analyze micelles morphology and size in aqueous media. Analytical solution of simplified DVS equations, displayed all possible shapes of micelles spanning spheroids, lamellas, and cylinders. Now we shall apply the equations to problems related to cell motility and growth factors. For that, we need some simple modeling to make equations tractable and in some cases analytically solvable. First modeling consideration is that, cell membrane is locally spherical when it is mechanically equilibrated with environment and second, it moves freely. Analytical solution of the equations, for the models, shows that trace of the mixed curvature tensor of the cell membrane is, locally, pressure factor divided on membrane tension. The cell can control motility and growth factor, in the direction of less pressure, by modulating membrane tension, or grow in the less pressure direction, by keeping membrane tension locally constant. According to the equations, pressure factors come from symmetry braking in the gradient of electromagnetic tensor and four current, explaining cell polarization in the direction of less pressure.

Similar Spectral Power Densities Within the Schumann Resonance and a Large Population of Quantitative Electroencephalographic Profiles: Supportive Evidence for Koenig and Pobachenko.

In 1954 and 1960 Koenig and his colleagues described the remarkable similarities of spectral power density profiles and patterns between the earth-ionosphere resonance and human brain activity which also share magnitudes for both electric field (mV/m) and magnetic field (pT) components. In 2006 Pobachenko and colleagues reported real time coherence between variations in the Schumann and brain activity spectra within the 6–16 Hz band for a small sample. We examined the ratios of the average potential differences (~3 μV) obtained by whole brain quantitative electroencephalography (QEEG) between rostral-caudal and left-right (hemispheric) comparisons of 238 measurements from 184 individuals over a 3.5 year period. Spectral densities for the rostral-caudal axis revealed a powerful peak at 10.25 Hz while the left-right peak was 1.95 Hz with beat-differences of ~7.5 to 8 Hz. When global cerebral measures were employed, the first (7–8 Hz), second (13–14 Hz) and third (19–20 Hz) harmonics of the Schumann resonances were discernable in averaged QEEG profiles in some but not all participants. The intensity of the endogenous Schumann resonance was related to the ‘best-of-fitness’ of the traditional 4-class microstate model. Additional measurements demonstrated real-time coherence for durations approximating microstates in spectral power density variations between Schumann frequencies measured in Sudbury, Canada and Cumiana, Italy with the QEEGs of local subjects. Our results confirm the measurements reported by earlier researchers that demonstrated unexpected similarities in the spectral patterns and strengths of electromagnetic fields generated by the human brain and the earth-ionospheric cavity.

Generalization of the Yang–Mills theory

We suggest an extension of the gauge principle which includes tensor gauge fields. In this extension of the Yang–Mills theory the vector gauge boson becomes a member of a bigger family of gauge bosons of arbitrary large integer spins. The proposed extension is essentially based on the extension of the Poincaré algebra and the existence of an appropriate transversal representations. The invariant Lagrangian is expressed in terms of new higher-rank field strength tensors. It does not contain higher derivatives of tensor gauge fields and all interactions take place through three- and four-particle exchanges with a dimensionless coupling constant. We calculated the scattering amplitudes of non-Abelian tensor gauge bosons at tree level, as well as their one-loop contribution into the Callan–Symanzik beta function. This contribution is negative and corresponds to the asymptotically free theory. Considering the contribution of tensorgluons of all spins into the beta function we found that it is leading to the theory which is conformally invariant at very high energies. The proposed extension may lead to a natural inclusion of the standard theory of fundamental forces into a larger theory in which vector gauge bosons, leptons and quarks represent a low-spin subgroup. We consider a possibility that inside the proton and, more generally, inside hadrons there are additional partons — tensorgluons, which can carry a part of the proton momentum. The extension of QCD influences the unification scale at which the coupling constants of the Standard Model merge, shifting its value to lower energies.

Conformational stability, molecular structure, vibrational, electronic, 1H and 13C spectral analysis of 3-pyridinemethanol using ab-initio/DFT method

The FT-IR and FT-Raman spectra of 3-pyridinemethanol (3PYRM) have been recorded in the regions 4000–400 and 4000–100 cm−1 respectively. The vibrational analysis of 3PYRM was carried out using wavenumbers computed by HF and DFT (B3LYP) methods with 6-311++G (d, p) basis set, along with experimental values. The conformational analyses were performed and the energies of the different possible conformers were determined. The total electron density and MESP surfaces of the molecules were constructed using B3LYP/6-311++G (d, p) method to display nucleophilic and electrophilic region globally. The HOMO and LUMO energies were measured and different reactivity descriptors are discussed the active sites of the molecule. Natural Bond Orbital Analysis is discussed and possible transition are correlated with the electronic transitions. Milliken's net charges and the atomic natural charges are also predicted. The 13C and 1H NMR chemical shifts were computed at the B3LYP/6-311++G (2d, p) level by applying GIAO theory and compared with the experimental spectra recorded using the high resolution of 100 MHz and 400 MHz NMR spectrometer with electromagnetic field strength 9.1T, respectively. The temperature dependence of the thermodynamic properties; heat capacity, entropy and enthalpy for the title compounds were also determined by B3LYP/6-311++G (d, p) method.

Optymalizacja metodyki pomiaru wieloczęstotliwościowego pola elektromagnetycznego stacji bazowych telefonii komórkowej

This paper presents the characteristics of the mobile phone base station (BS) as an electromagnetic field (EMF) source. The most common system configurations with their construction are described. The parameters of radiated EMF in the context of the access to methods and other parameters of the radio transmission are discussed. Attention was also paid to antennas that are used in this technology. The influence of individual components of a multi-frequency EMF, most commonly found in the BS surroundings, on the resultant EMF strength value indicated by popular broadband EMF meters was analyzed. The examples of metrological characteristics of the most common EMF probes and 2 measurement scenarios of the multisystem base station, with and without microwave relays, are shown. The presented method for measuring the multi-frequency EMF using 2 broadband probes allows for the significant minimization of measurement uncertainty. Equations and formulas that can be used to calculate the actual EMF intensity from multi-frequency sources are shown. They have been verified in the laboratory conditions on a specific standard setup as well as in real conditions in a survey of the existing base station with microwave relays. Presented measurement methodology of multi-frequency EMF from BS with microwave relays, validated both in laboratory and real conditions. It has been proven that the described measurement methodology is the optimal approach to the evaluation of EMF exposure in BS surrounding. Alternative approaches with much greater uncertainty (precaution method) or more complex measuring procedure (sources exclusion method) are also presented).

Problem of Electromagnetoviscoelasticity for Multiply Connected Plates

A method for solving the problem of electromagnetoviscoelasticity for multiply connected plates is proposed. The small-parameter method is used to reduce this problem to a recursive sequence of problems of electromagnetoelasticity, which are solved by using complex potentials. A procedure is developed to determine, using complex potentials, approximations of the basic characteristics (stresses, electromagnetic-field strength, electromagnetic-flux density) of the electromagnetoelastic state at any time after application of a load. A plate with an elliptic hole is considered as an example. The variation in the electromagnetoelastic state of the multiply connected plate with time is studied

Power Generation Using Magnetic Nanofluids in Millimeter-Sized Channel With In-Phase Mode of Magnetization

Magnetic nanofluids (MNFs) are an interesting energy harvesting source. Oil- or water-based MNFs include a certain percentage of magnetized nanoparticles (MNPs) and have unique features that vary with the strength of the external electromagnetic field [1]-[3]. For MNFs, it was proved that the electric power generation could be achieved by using waste heat energy [4]. In this work, the flow energy harvesting was experimentally and numerically investigated in a millimeter-sized channel by using an externally applied permanent magnet to control the magnetizing direction of the MNPs. When the MNF flows through a cross-sectional area of the coil loop, the electric current can be obtained by following the Faraday's law because the MNPs act as permanent magnets [5]. When the MNFs are used for flow energy harvesting, the main issue is the in-phase mode alignment of the MNPs magnetization with the coil loop. Although without the in-phase mode the electric power cannot be generated, as the net magnetization of the MNF is zero, most of the previous research works have not considered it. Thus, to implement this mode, we proposed an externally applied magnetic field generated by a cylindrically shaped permanent magnet. Short and closed Teflon tubing with a 3 mm inner diameter, containing the MNF, was located inside long silicon tubing and moved along the positive and negative direction by a pump. Then, the generated voltages were measured and exhibited similar results to those obtained analytically.

Poynting Theorem, Relativistic Transformation of Total Energy–Momentum and Electromagnetic Energy–Momentum Tensor

We address to the Poynting theorem for the bound (velocity-dependent) electromagnetic field, and demonstrate that the standard expressions for the electromagnetic energy flux and related field momentum, in general, come into the contradiction with the relativistic transformation of four-vector of total energy–momentum. We show that this inconsistency stems from the incorrect application of Poynting theorem to a system of discrete point-like charges, when the terms of self-interaction in the product \({\varvec{j}} \cdot {\varvec{E}}\) (where the current density \({\varvec{j}}\) and bound electric field \({\varvec{E}}\) are generated by the same source charge) are exogenously omitted. Implementing a transformation of the Poynting theorem to the form, where the terms of self-interaction are eliminated via Maxwell equations and vector calculus in a mathematically rigorous way (Kholmetskii et al., Phys Scr 83:055406, 2011), we obtained a novel expression for field momentum, which is fully compatible with the Lorentz transformation for total energy–momentum. The results obtained are discussed along with the novel expression for the electromagnetic energy–momentum tensor.

Nonminimally coupled Einstein-Maxwell model in a non-Riemann spacetime with torsion

A system of field equations for an Einstein-Maxwell model with $RF^2$-type nonminimal coupling in a non-Riemannian space-time with a non-vanishing torsion is derived and the resulting field equations are expressed in terms of the Riemannian quantities based on a metric with a Lorentzian signature. The torsion is generated by the gradients of the electromagnetic field invariants. An electromagnetic constitutive tensor is introduced in the formulation of the field equations.

Geometry of Killing spinors in neutral signature

We classify the supersymmetric solutions of minimal N = 2 gauged supergravity in four dimensions with neutral signature. They are distinguished according to the sign of the cosmological constant and whether the vector field constructed as a bilinear of the Killing spinor is null or non-null. In neutral signature the bilinear vector field can be spacelike, which is a new feature not arising in Lorentzian signature. In the non-null case, the canonical form of the metric is described by a fibration over a three-dimensional base space that has holonomy with torsion. We find that a generalized monopole equation determines the twist of the bilinear Killing field, which is reminiscent of an Einstein–Weyl structure. If, moreover, the electromagnetic field strength is self-dual, one gets the Kleinian signature analogue of the Przanowski–Tod class of metrics, namely a pseudo-hermitian spacetime determined by solutions of the continuous Toda equation, conformal to a scalar-flat pseudo-Kähler manifold, and admitting in addition a charged conformal Killing spinor. In the null case, the supersymmetric solutions define an integrable null Kähler structure. In the non-null case, the manifold is a fibration over a Lorentzian Gauduchon–Tod base space. Finally, in the null class, the metric is contained in the Kundt family, and it turns out that the holonomy is reduced to . There appear no self-dual solutions in the null class for either sign of the cosmological constant.

Radiation from a relativistic Poynting jet: some general considerations

We provide estimates for the flux and maximum frequency of radiation produced when the magnetic field in a relativistic, highly magnetized, jet is dissipated and particles are accelerated using general considerations. We also provide limits on the jet Lorentz factor and magnetization parameter from the observed flux. Furthermore, using the Lorentz invariance of scalar quantities produced with electromagnetic tensor, we provide constraints on particle acceleration, and general features of the emergent radiation. We find that the spectrum below the peak softens with decreasing frequency. This spectral feature might be one way of identifying a magnetic jet.

Euclidean Complex Relativistic Mechanics: A New Special Relativity Theory

Relativity Theory (RT) was fundamental for the development of Quantum Mechanics (QMs). Special Relativity (SR), as is applied until now, cancels the transitive attribute in parallelism, when three observers are related, because Lorentz Boost (LB) is not closed transformation. In this presentation, considering Linear Spacetime Transformation (LSTT), we demand the maintenance of Minkowski Spacetime Interval (S2). In addition, we demand this LSTT to be closed, so there is no need for axes rotation. The solution is the Vossos Matrix (ΛB) containing real and imaginary numbers. As a result, space becomes complex, but time remains real. Thus, the transitive attribute in parallelism, which is equivalent to the Euclidean Request (ER), is also valid for moving observers. Choosing real spacetime for the unmoved observer (O), all the natural sizes are real, too. Using Vossos Transformation (VT) for moving observers, the four-vectors’ zeroth component (such as energy) is real, in contrast with spatial components that are complex, but their norm is real. It is proved that moving (relative to O) human O' meter length, according to Lorentz Boost (LB). In addition, we find Rotation Matrix Vossos-Lorentz (RBL) that turns natural sizes’ complex components to real. We also prove that Speed of Light in Vacuum (c) is invariant, when complex components are used and VT is closed for three sequential observers. After, we find out the connection between two moving (relative to O) observers: X"= ΛLO"(o) ΛLO(O') X', using Lorentz Matrix (ΛL). We applied this theory, finding relations between natural sizes, that are the same as these extracted by Classic Relativity (CR), when two observers are related (i.e. relativistic Doppler shift is the same). But, the results are different, when more than two observers are related. VT of Electromagnetic Tensor (Fμv), leads to Complex Electromagnetic Fields (CEMFs) for a moving observer. When the unmoved observer O and a moving observer O' are related, O measures the same Real Electromagnetic Fields (REMFs) as those are given, using LB, but O' measure CEMFs with the same formula. Complex Electromagnetic Tensor (F'B) turns to Real Electromagnetic Tensor (F') using the formula . When there are two moving (relative to O) observers O' and O", their real electromagnetic tensors are related, using the form F" = ΛLO"(O) ΛLO(O) F' [ΛLO"(O') ΛLO(O')]T. In addition, we prove that the relation between two moving (relative to O) observers, when they use Real Coordinates (RCs), causes a real rotation between their frames. The turn is opposite to the turn of Thomas and has a little different measure, when the velocities are small. We apply these to the Uniform Circular Motion (UCM) and to the Hydrogen Atom (H), considering that the Proton (p) is the unmoved observer O and the laboratory observer O' has infinitesimal velocity. Using Perturbation Theory (PT) we calculate the position of the fine structure peaks of the atomic spectrum. The result is better not only than this extracted using P. Dirac Theory, but also than that extracted using L. H. Thomas Method.

Statistical analysis of electromagnetic radiation measurements in the vicinity of GSM/UMTS base station installed on buildings in Serbia.

As a result of dense deployment of public mobile base stations, additional electromagnetic (EM) radiation occurs in the modern human environment. At the same time, public concern about the exposure to EM radiation emitted by such sources has increased. In order to determine the level of radio frequency radiation generated by base stations, extensive EM field strength measurements were carried out for 664 base station locations, from which 276 locations refer to the case of base stations with antenna system installed on buildings. Having in mind the large percentage (42 %) of locations with installations on buildings, as well as the inevitable presence of people in their vicinity, a detailed analysis of this location category was performed. Measurement results showed that the maximum recorded value of total electric field strength has exceeded International Commission on Non-Ionizing Radiation Protection general public exposure reference levels at 2.5 % of locations and Serbian national reference levels at 15.6 % of locations. It should be emphasised that the values exceeding the reference levels were observed only outdoor, while in indoor total electric field strength in no case exceeded the defined reference levels.

Path integral for spinning particle subjected to the constant electromagnetic field

The problem of the Dirac particle submitted to a wave [Formula: see text] of a four-dimensional constant electromagnetic tensor is solved with the path integral approach via the use of Lorentz transformation and with an adequate choice for the velocity of the mobile referential.We show that the supersymmetric action associated to the pair [Formula: see text] can be determined from that associated to the pair [Formula: see text] and from that associated to the pair [Formula: see text] following simple relations.The wave functions and the energy spectrums are thus exactly determined and tested. Special cases are considered as well.

Gyromagnetic gs factors of the spin-1/2 particles in the (1/2+-1/2--3/2-) triad of the four-vector spinor, ψμ, irreducibility and linearity

The gauged Klein–Gordon equation, extended by a gsσμνFμν/4 interaction, the contraction of the electromagnetic field strength tensor, Fμν, with the generators, σμν/2, of the Lorentz group in (1/2, 0) ⊕ (0, 1/2), and gs being the gyromagnetic factor, is examined with the aim to find out as to what extent it qualifies as a wave equation for general relativistic spin-1/2 particles transforming as (1/2, 0) ⊕ (0, 1/2) and possibly distinct from the Dirac fermions. This equation can be viewed as the generalization of the gs = 2 case, known under the name of the Feynman–Gell-Mann equation, the only one which allows for a bilinearization into the gauged Dirac equation and its conjugate. At the same time, it is well-known a fact that a gs = 2 value can also be obtained upon the bilinearization of the nonrelativistic Schrödinger into nonrelativistic Pauli equations. The inevitable conclusion is that it must not be necessarily relativity which fixes the gyromagnetic factor of the electron to g(1/2) = 2, but rather the specific form of the primordial quadratic wave equation obeyed by it, that is amenable to a linearization. The fact is that space-time symmetries alone define solely the kinematic properties of the particles and neither fix the values of their interacting constants, nor do they necessarily prescribe linear Lagrangians. Information on such properties has to be obtained from additional physical inputs involving the dynamics. We here provide an example in support of the latter statement. Our case is that the spin-1/2- fermion residing within the four-vector spinor triad, ψμ ~ (1/2+-1/2--3/2-), whose sectors at the free particle level are interconnected by spin-up and spin-down ladder operators, does not allow for a description within a linear framework at the interacting level. Upon gauging, despite transforming according to the irreducible (1/2, 1) ⊕ (1, 1/2) building block of ψμ, and being described by 16-dimensional four-vector spinors, though of only four independent components each, its Compton scattering cross sections, both differential and total, result equivalent to those for a spin-1/2 particle described by the generalized Feynman–Gell-Mann equation from above (for which we provide an independent algebraic motivation) and with g(1/2-) = -2/3. In effect, the spin-1/2- particle residing within the four-vector spinor effectively behaves as a true relativistic "quadratic" fermion. The g(1/2-) = -2/3 value ensures in addition the desired unitarity in the ultraviolet. In contrast, the spin-1/2+ particle, in transforming irreducibly in the (1/2, 0) ⊕ (0, 1/2) sector of ψμ, is shown to behave as a truly linear Dirac fermion. Within the framework employed, the three spin sectors of ψμ are described on equal footing by representation- and spin-specific wave equations and associated Lagrangians which are of second-order in the momenta.

The Effect of Electromagnetic Field Generated by a Mobile Phone on the Performance of a SPECT Scanner: A Quantitative Study.

The aim of the current attempt was quantitative investigation of the electromagnetic interference (EMI) of a mobile phone with the function of a SPECT gamma camera during data acquisition. We tested the effect of a mobile phone, in both ringing mode and standby mode, on one SPECT gamma camera during scanning a cylindrical phantom containing 5.4 mCi (99m)Tc. The experiment was performed for different distances of 10, 12, 14, 16, 18, 20, 25, and 30 cm between mobile phone and head of the scanner, and for different head angles of 0, 30, 60, 90, 120, 150, and 180 degrees. A RF-EMF meter measured strength of electromagnetic field throughout the study. Statistically significant decrease in count number was considered to be electromagnetic interference. There was significant reduction in the recorded counts during ringing of the mobile phone in all studied distances. For gamma camera, fixed at a distance, there was no uniform pattern of reduction of the counts at different angles between two operation modes of the mobile phone. A mobile phone, at close distance, can be a sensible source of electromagnetic field, disturbing the normal function of a gamma camera.

System-Based Safety Tenets Applied to the Extra-High Voltage Transmission Line Design for Common Uses of Highway Right-of-Way

The rapidly increasing demand for electricity in recent years resulted in increasing needs of electrical system capacity and deployment for alternate uses of highway right-of-way (ROW) for the purpose of electric power generation, transmission, and distribution. In this framework, a systems approach—fundamental principles of system dynamics for identifying, understanding, and analyzing safety requirements of the extra-high voltage power line (EHV)—is used to objectively focus on two main safety issues related to the design and the risk of the EHV transmission line within highway ROW: (1) assess the design and the operation, and (2) evaluate causally related impacts on the public and workers’ safety that matter. A generalized model of the electromagnetic fields distribution and the clearance model are developed for the analysis of the causally related impacts of a conceptual design and the reliability of materials of construction of the electric systems by introducing the number of exposed individuals and the level of the environmental impacts as a second dimension in addition to the risk factors. A worst-case design scenario is evaluated. Sensitivity analysis of effects of the design attributes such as the route configuration, over voltages, and conductor clearance is performed by determining the magnitude of the electromagnetic field strengths and predicting the resulting maximum voltage. Information obtained on the structural design scenario, conductor size and configuration, insulators, and connectors is of value in determining the safety of the design for operation at extra-high voltages within highway ROW.

Plasmonic Spectroscopy: The Electromagnetic Field Strength and its Distribution Determine the Sensitivity Factor of Face-to-Face Ag Nanocube Dimers in Solution and on a Substrate

Using the DDA method, the spectral sensitivity of a 42 nm Ag nanocube dimer oriented face-to-face in solution and placed on a substrate was investigated. The sensitivity factor was calculated as a function of both the plasmonic band that was analyzed and the refractive index of the substrate. We found that the maximum value of the electromagnetic field intensity of a given plasmonic band is not directly proportional to its extinction intensity. Also, the sensitivity factor of a plasmonic band does not depend on its extinction intensity, but rather, it is a function of the maximum value of the plasmonic electromagnetic field intensity distribution. The presence of a high refractive index substrate drastically affects the extinction intensity of a given band and selectively enhances specific plasmonic bands on the basis of their electromagnetic field distribution. The distribution of the electromagnetic field intensity on the surface of the Ag nanocube dimer is also affected by the presence of a substrate w...