Electromagnetic Tensor Research Articles

Cylindrically symmetric self-sustaining solutions in some models of nonlinear electrodynamics

In this article, we discuss the extension of the Melvin solution for the geon to some models of non-linear electrodynamics with the exact form of the Lagrangian, in particular, for a conformally invariant model (CNED), whose Lagrangian depends on the second and fourth order invariants of the electromagnetic field tensor.

EM-FOR: simple and low-cost force on a straight current-carrying conductor in a magnetic field experimental kit

In this study, we design and construct a low-cost experimental kit for the force on a straight current-carrying conductor in a magnetic field experiment, namely EM-FOR. The kit consists of several pairs of rectangular-shaped permanent magnets with different polarities facing each other on a U-shaped aluminium casing as the source of the magnetic field, a straight copper wire at the centre between the two magnets as the electrical conductor, conductor rings and connecting wires to connect conductor and electrical source, and an electronic balance to measure the magnitude and to determine the direction of the force on a straight current-carrying conductor in a magnetic field. The design of the EM-FOR experimental kit was validated by determining the magnitude and direction of the force on a straight current-carrying conductor in a magnetic field for normal and reverse connections to a power supply. The constructed kit can be utilized for three experiments: the effects of applied current, conductor length and electromagnetic field strength on the force on a straight current-carrying conductor in a magnetic field.

Schwinger effect and a uniformly accelerated observer

This article investigates the Schwinger effect for fermions with background electric and magnetic fields of constant strengths from the point of view of a uniformly accelerated or the Rindler observer. The Dirac equation is solved in a closed form, and the field quantisation in the (3+1)-dimensional Rindler spacetime is performed. The orthonormal local in and out modes for the causally disconnected right and left wedges and the Bogoliubov relations between them are obtained. Next, the global modes are constructed to cover the whole spacetime, and the Bogoliubov relationship between the local and global operators is found. Using them the squeezed state expansion of the global vacuum in terms of local states is acquired and accordingly, the spectra of created particles is found. Clearly, there are two sources of particle creation in this scenario – the Schwinger as well as the Unruh effects. Our chief aim is to investigate the role of the strength of the background electromagnetic fields on the spectra of created particles. We also discuss very briefly some possible implication of this result in the context of quantum entanglement.

Optical properties of planar plasmon active surfaces modified with gold nanostars

The article discusses the experimental and theoretical results of studying the optical properties for planar quartz surfaces modified with gold nanostars using Surface-Enhanced Raman Spectroscopy (SERS). Surfaces functionalized with nanoparticles, prototypes of optical sensors, have been obtained. It is shown that the obtained experimental Raman signal enhancement from the dye rhodamine 6G (R6G) can be at least order 104. The paper presents the results of calculation, synthesis and study of the optical and morphological properties of such structures. A complex method for creating and evaluating the optical properties of planar nanostructures and evaluating their optical properties is proposed. The method includes the approaches based on mathematical modeling using finite differences in the time domain (FDTD - Finite-Difference Time-Domain) evaluating electromagnetic field strengths near the surfaces of star-shaped gold nanoparticles in colloidal solutions and on a silicon surface. During the simulation, we studied such parameters as the particle size, the wavelength of the exciting radiation, and the dependence of the effective amplification of the electromagnetic field on the morphological parameters of the star. The theoretical approach to the calculation of such structures is shown to be promising for the subsequent chemical synthesis described in the article and the study of optical properties. In this paper, a theoretical calculation of the parameters of the electric field and optical properties is carried out near star-shaped nanoparticles of varying sizes. These parameters were calculated by the finite difference method in the time domain. The task included finding the optimal sizes of nanoparticles as well as varying the thickness of the surface layers in order to obtain the maximum scattering values and further use of similar structures in SERS experiments. Also, within the framework of this work, syntheses of star-shaped nanoparticles was carried out, their optical and morphological properties were studied, quartz surfaces were functionalized with nanoparticles, and sensor prototypes were created in order to further assess the Raman signal amplification. Based on the results of mathematical modeling, the optimal sizes for the synthesis of star-shaped NPs were determined. Synthesis of NPs was carried out by a chemical method using seeds. To carry out the experimental part, SERS spectra were obtained using Centaur U spectrometer (OOO NanoScanTechnology, Russia). The spectrometer was equipped with three different laser sources: 632.8 nm He-Ne laser (17 mW), 532 nm and 473 nm DPSS lasers (45 mW). During the experiment, a He-Ne laser with λ = 632 nm and DPSS laser with λ = 532 nm were used to match the excitation of the plasmon maximum for the nanostars. The optical scheme of the spectrometer included an Olympus BX41 microscope (Olympus, Japan) with a 100× objective (NA 0.9) for positioning the beam and collecting scattered photons. The monochromator of the spectrometer had a focal length of 800 mm. A holographic diffraction grating of 300 gr/mm, and was equipped with a 1024×256 pixel thermoelectric cooled CCD detector (Andor Tech., UK). As a result of the paper, surfaces functionalized by nanoparticles were obtained prototypes of optical sensors. It is shown that the experimental gain of the Raman signal can be no less than 104 times. The presented data will serve as the basis for obtaining the required sizes of nanostars in the methods of the controlled chemical synthesis of colloidal nanoparticles. The results presented in the article can be applied to the development of biocompatible and highly sensitive optical sensors based on the effect of Raman scattering of light.

ИССЛЕДОВАНИЕ ВОЗДЕЙСТВИЯ ИМПУЛЬСНОГО МАГНИТНОГО ПОЛЯ НА БИОЛОГИЧЕСКУЮ АКТИВНОСТЬ 1,1-БИС(1H-ИМИДАЗОЛ-1-ИЛ) МЕТАНИМИНА

The paper is devoted to the study of pulsed magnetic field impacting at the biological activity of a newly synthesized antifungal drug based on the imidazole 1,1-Bis(1H-imidazole-1-il)metanimine. Two experimental methods were consistently used for the study like as the treatment of an antifungal drug through installation of electromagnetic pulse emission and analysis of the results of treatment with the disco-diffusion method. During the experiments, the hypothesis of an increase in the antimycotic activity of an antifungal drug under the influence of a pulsed magnetic field was tested. The monitoring objects of the experiment were strains of the Penicillium adametzoides and the Aspergillus flavus. The antifungal drug was treated on the magnetic-pulse installation at the electromagnetic field strength H=(0.09÷0.27)∙106 A/m at frequency f=40 kHz with the number of pulses n=1. The analysis of experimental results has shown that the pulsed magnetic field has an effect on the antifungal drug, during which there is an inhibition of the growth of the colony of Aspergillus flavus by 71%. At the same time, in the process of studying the effect of the unirradiated antifungal drug impact at the grown colonies of the Aspergillus flavus, were not recorded the lysis zones increasing. Studying of the effect of the irradiated antifungal drug impact at the inhibition of the growth of the colony of the Penicillium adametzioides, there was not recorded lysis zones significant increasing. At the same time, during the experiment on the research of effect of the antifungal drug that was treated with a pulsed magnetic field at the grown colonies of the fungus Penicillium adametzioides, the maximum significant increase in lysis zones by 13% was discovered.

Deuteron electromagnetic form factors and tensor polarization observables in the framework of the hard-wall AdS/QCD model

We study the electromagnetic form factors and tensor polarization observables of the deuteron in the framework of the hard-wall AdS/QCD model. We find a profile function for the bulk twist vector field, which describes the deuteron on the boundary and fix the infrared boundary cut-off of AdS space in accordance with the ground state mass of the deuteron. We obtain the deuteron charge monopole, quadrupole, and magnetic dipole form factors and tensor polarization observables from the bulk Lagrangians for the deuteron and photon field interactions. We plot the momentum transfer dependence of the form factors and tensor polarization observables and compare our numerical results with those in the soft-wall model and experimental data.

Nonlocal gluon condensates in QCD sum rules

Nonlocal gluon condensates are vacuum expectations of the product of gluon field strength tensors. Short-distance expansions of two-, three-, and four-gluon condensates are presented up to dimension-8 local operators. We propose a method for calculating the Wilson coefficients based on the presented expansions and the Feynman diagram technique in the background field approach. The method is demonstrated using the glueball current correlators as examples. Methodological aspects of the background field approach are discussed in relation to glueball studies within QCD sum rules. We confirm the results for Operator Product Expansion (OPE) of the two-gluon $0^{\pm +}$ glueball current correlators and calculate additional contributions coming from dimension-6 four-quark condensate and dimension-8 mixed quark-gluon condensates. The OPEs used in QCD sum rules for three-gluon $0^{\pm +}$ glueballs are revisited up to dimension-6 order.

Motion of charged particles in spacetimes with magnetic fields of spherical and hyperbolic symmetry

The motion of charged particles in spacetimes containing a submanifold of constant positive or negative curvature is considered, with the electromagnetic tensor proportional to the volume two-form form of the submanifold. In the positive curvature case, this describes spherically symmetric spacetimes with a magnetic monopole, while in the negative curvature case, it is a hyperbolic spacetime with magnetic field uniform along hyperbolic surfaces. Constants of motion are found by considering Poisson brackets defined on a phase space with gauge-covariant momenta. In the spherically-symmetric case, we find a correspondence between the trajectories on the Poincar\'{e} cone with equatorial geodesics in a conical defect spacetime. In the hyperbolic case, the analogue of the Poincar\'{e} cone is defined as a surface in an auxiliary Minkowski spacetime. Explicit examples are solved for the Minkowski, $\mathrm{AdS}_4\times S^2$, and the hyperbolic AdS-Reissner--Nordstr\"{o}m spacetimes.

Electromagnetic Radiation Mechanism Analysis and Field Strength Prediction of an Elementary Digital Inverter with Cables

In this paper, common mode (CM) and differential mode (DM) far-field radiation models of a typical digital inverter with cables are built up to predict electromagnetic field strength and analyze field characteristics. The CM current model and its analyses are based on the imbalance difference method. It is found out that the voltage between the drain and the source electrodes of upper transistor is the key equivalent source of electromagnetic interference (EMI). Far-field radiation strength of the digital inverter in free space is predicted by using the asymmetrical antenna radiation method and current loop radiation method. The accuracy of these methods is verified by the CST electromagnetic simulation results in the frequency range from 1 MHz to 400 MHz. Furthermore, the radiation models are improved by using the mirror method, which enables to include the reflection effect of the metal ground plane at the electromagnetic compatibility (EMC) test site. Both the results of measurements in a semi-anechoic chamber and the simulation results confirm the proposed electromagnetic radiation prediction method.

Magnetic monopoles in two time dimensions

The observation of magnetic monopoles would lead to a symmetrization of Maxwell’s equations and provide explanations of fundamental properties such as the quantization of electric charge. Yet, in four dimensions, the covariant electromagnetic field tensor yields an action whose resulting field equations establish the absence of a magnetic charge. We here study the existence of magnetic monopoles in an extended space–time with a second time dimension, and construct the higher-dimensional gauge potential. This motivates the use of the Kalb–Ramond field, upon which a Kaluza–Klein-like reduction is performed under the assumption that the two time dimensions have no co-dependency. The resulting 5D electrodynamics contains a generalized version of Maxwell’s equations which contain magnetic charge densities whose source potential obeys a five-dimensional wave equation. As a second time dimension only acts on small length scales in the order of the Planck length, we provide a theory with symmetrized Maxwell’s equations including magnetic monopoles which do not violate current experimental evidence. We finally discuss the subsequent quantization of the electric charge as well as the weak interaction, equivalent to the violation of time reversal.

Joint focusing inversion of marine controlled-source electromagnetic and full tensor gravity gradiometry data

We have developed an approach for integrating the interdependent information of different geophysical methods to obtain a self-consistent geophysical model in offshore exploration. Electromagnetic (EM) and gravity data complement seismic data by providing information about the physical properties of prospective reservoir rocks. We have combined marine EM and gravity gradiometry geophysical data in joint inversion using a joint focusing stabilizer. The method enforces coupling between different physical models and simultaneously promotes focused images of the targets. We also consider the importance of using robust norms to analyze data collected by marine controlled-source EM surveys. The practical effectiveness of the developed method is illustrated by a case study of integrating and imaging marine multiphysics data collected in the Nordkapp Basin, Barents Sea, Norway.

Lightning the Electromagnetic Pulse Coupling of Airborne Secondary Radar Electronic Equipment Using Intelligent Computing

In order to analyze the lightning coupling of the airborne secondary radar electronic equipment, this study analyzes the transient electromagnetic field strength of the airborne secondary radar electronic equipment and the current density distribution on the aircraft surface when the lightning directly hits the aircraft based on the simulation technology of the transmission-line matrix method. On this basis, the simulation research of field distribution and cable coupling is further carried out. Through the simulation calculation, it can be seen that when the lightning strikes the aircraft, the current density is relatively small in the continuous parts of the upper and lower surfaces of the fuselage and the middle of the wing. In addition to the areas where the lightning current is easily attached, structural irregularities such as windows, engines, front and rear edges of wings, and outboard antennas are often affected by edge effects, and the current density is often concentrated, requiring key protection. For more sensitive electronic equipment, the cable connected to it can be considered to use an appropriate type of shielded cable to achieve the shielding effect on the electromagnetic environment.

Magnetized Bianchi Type-VI0 String Cosmological Model for Anti-Stiff Fluid in General Relativity

In this paper, we have investigated magnetized Bianchi type-VI0 string cosmological model for anti-stiff fluid in general relativity. We assume that F23 is the only survival component of electromagnetic field tensor Fij. For the absolute determination of the model, we assume the expansion in the model is proportional to the shear. The common measures of the Einstein’s field equations for the cosmological model have been acquired under the assumption of anti-stiff fluid i.e. p + ρ = 0, where ρ and p are the rest energy density and the pressure of the fluid, respectively. The physical and geometrical outcomes of the model in the presence of magnetic field are discussed.

Light-by-light scattering at future e^+e^- colliders

We study the sensitivity of possible CLIC and FCC-ee measurements of light-by-light scattering to old and new physics, including the Heisenberg–Euler Lagrangian in the Standard Model with possible contributions from loops of additional charged particles or magnetic monopoles, the Born–Infeld extension of QED, and effective dimension-8 operators involving four electromagnetic field strengths as could appear in the Standard Model Effective Field Theory. We find that FCC-ee measurements at 365 GeV and CLIC measurements at 350 GeV would be sensitive to new physics scales of half a TeV in the dimension-8 operator coefficients, and that CLIC measurements at 1.4 TeV or 3 TeV would be sensitive to new physics scales sim 2 TeV or 5 TeV at 95% CL, corresponding to probing loops of new particles with masses up to sim 3.7 TeV for large charges and/or multiple species. Within Born–Infeld theory, the 95% CL sensitivities would range from sim 300 GeV to 1.3 or 2.8 TeV for the high-energy CLIC options. Measurements of light-by-light scattering would not exclude monopole production at FCC-hh, except in the context of Born–Infeld theory.

The Space-Time Metric Outside a Pulsating Charged Sphere

We consider the problem of determining the dynamics of the electromagnetic field generated outside a ball whose charge changes depending on time. We are in conditions of perfect symmetry and the electric field is considered to be radial. This is not a simplification since, under such a hypothesis, the magnetic field does not develop. Thus, it is first necessary to find out the appropriate modeling equations. These are obtained by writing a suitable energy tensor that combines the classical electromagnetic stress-energy tensor with a special kind of mass tensor. The next step is to show that it is possible to solve Einstein’s equations by plugging the new tensor on the right-hand side. Interesting connections with some classical solutions related to black holes are finally established.

Purcell factors and Förster-resonance energy transfer in proximity to helical structures

Both spontaneous emission and resonant energy transfer can be enhanced significantly when the emitter is placed in the vicinity of metallic or crystal structures. This enhancement can be described using the electromagnetic Green tensor and is determined by the dominant surface modes of the structure. Here we use the eigenpermittivity formalism to derive the spontaneous emission and FRET rates in the quasistatic regime in a two-constituent medium with an anisotropic inclusion. We then apply our results to a helical structure supporting synchronous vibrations and evaluate the contribution of these modes, which are associated with a strong and delocalized response. We show that this contribution can result in large Purcell factors and long-range FRET, which oscillates with the helix pitch. These findings may have implications in understanding and controlling the interactions of molecules close to helical structures such as the microtubules.

Polarizability of Microparticles in Relativistic Field Theory

The article determine a relativistic tensor of the second rank containing the vectors of the electric and magnetic polarization of the medium, based on the Maxwell equations and the determination of the charge density and polarization current of a structural microparticle. Using this tensor and the electromagnetic field tensor, the relativistic lagrangian of the interaction an electromagnetic field with a structural microparticle is obtained, taking into account the polarization of its structural elements. Based on the induced moments, the relativistic lagrangian of the interaction an electromagnetic field with a structural microparticle is constructed with considering the electric and magnetic polarizabilities.

Magnetization of bioethanol-gasoline fuel blends for development combustion energy and reducing exhaust gas emissions

The effect of the magnetization field on molecular interactions of the bioethanol-gasoline fuel blends was investigated. This technique was promoted to escalate both the increase in combustion energy and reduce emissions in the internal combustion engine. The bioethanol and gasoline fuel are used for the single-cylinder four-stroke engine with different mixtures, namely E0, E10, E20, and E30, serially. Distinguish of electromagnetic field strength with various intensity was given into the fuel by lower than 1,500 Gauss. The absorption intensity and the functional groups of the fuel molecules are characterized in detail by Fourier Transform Infra-Red (FTIR) spectroscopy. The exhaust gas emission and the fuel blends energy are performed using a gas analyzer and calorimeter bomb. By increasing the magnetic field, the de-clustering of the fuel molecules is demonstrated by growing the absorption intensity to be advanced. There is no change in the chemical composition of the fuel as the magnetic induction was enforced. Reduction of namely Carbon monoxide (CO), Nitrogen monoxide (NO), Nitrogen oxides (NOx), and Sulphur Dioxide (SO2) gas emissions was attained to be 29 %, 25 %, 26 %, and 31 % using a magnetic field of 1,419.57 Gauss, respectively, compared to gasoline fuel without magnetic condition. The greater reduction occurs by employing E30 fuel with the same magnetic intensity, achieved up to 38 %, 42 %, 70 %, and 63 %, regularly. The magnetization treatment leads to improved combustion quality with efficiency increases up to 11.32 %. It contributes to perfect combustion in a single-cylinder four-stroke engine system. Reducing gas emissions can also bring a good environmental impact in the life, although the heat energy gradually deteriorated as the fuel utilized more bioethanol blends

Cold Quark–Gluon Plasma EOS Applied to a Magnetically Deformed Quark Star with an Anomalous Magnetic Moment

We consider a QCD cold-plasma-motivated Equation of State (EOS) to examine the impact of an Anomalous Magnetic Moment (AMM) coupling and small shape deformations on the static oblate and prolate core shapes of quark stars. Using the Fogaça QCD-motivated EOS, which shifts from the high-temperature, low-chemical-potential quark–gluon plasma environment to the low-temperature, high-chemical-potential quark stellar core environment, we consider the impact of an AMM coupling with a metric-induced shape deformation parameter in the Tolman–Oppenheimer–Volkov (TOV) equations. The AMM coupling includes a phenomenological scaling that accounts for the weak and strong field characteristics in dense matter. The EOS is developed using a hard gluon and soft gluon decomposition of the gluon field tensor and using a mean-field effective mass for the gluons. The AMM is considered using the Dirac spin tensor coupled to the EM field tensor with quark-flavor-based magnetic moments. The shape parameter is introduced in a metric ansatz that represents oblate and prolate static stellar cores for modified TOV equations. These equations are numerically solved for the final mass and radius states, representing the core collapse of a massive star with a phase transition leading to an unbound quark–gluon plasma. We find that the combined shape parameter and AMM effects can alter the coupled EOS–TOV equations, resulting in an increase in the final mass and a decrease in the final equatorial radius without collapsing the core into a black hole and without violating causality constraints; we find maximum mass values in the range 1.6 Mʘ < M < 2.5 Mʘ. These states are consistent with some astrophysical, high-mass magnetar/pulsar and gravity wave systems and may provide evidence for a core that has undergone a quark–gluon phase transition such as PSR 0943 + 10 and the secondary from the GW 190814 event.

Exact universal chaos, speed limit, acceleration, Planckian transport coefficient, “collapse” to equilibrium, and other bounds in thermal quantum systems

We introduce “local uncertainty relations” in thermal many body systems. Using these relations, we derive basic bounds. These results include the demonstration of universal non-relativistic speed limits (regardless of interaction range), bounds on acceleration or force/stress, acceleration or material stress rates, transport coefficients (including the diffusion constant and viscosity), electromagnetic or other gauge field strengths, correlation functions of arbitrary spatio-temporal derivatives, Lyapunov exponents, and thermalization times. We further derive analogs of the Ioffe–Regel limit. These bounds are relatively tight when compared to various experimental data. In the ħ→0 limit, all of our bounds either diverge (e.g., the derived speed and acceleration limit) or vanish (as in, e.g., our viscosity and diffusion constant bounds). Our inequalities hold at all temperatures and, as corollaries, imply general power law bounds on response functions at both asymptotically high and low temperatures. Our results shed light on how apparent nearly instantaneous effective “collapse” to energy eigenstates may arise in macroscopic interacting many body quantum systems. We comment on how random off-diagonal matrix elements of local operators (in the eigenbasis of the Hamiltonian) may inhibit their dynamics.