Periodic Electromagnetic Field Research Articles

Modelling assisted tunneling on the Bloch sphere using the Quantum Composer

The Bloch sphere representation is a geometric model for all possible quantum states of a two-level system that can be used to describe the time dynamics of a qubit. As explicit application, we consider the time dynamics of a particle in a double-well potential. In particular, we adopt a recent method for off-resonant excitations, the so-called SUPER principle (Swing Up of the quantum emitter population) driven by periodic electromagnetic fields, to the context of quantum tunnelling. We show that the tunnelling probability can be enhanced significantly when an appropriate oscillation of the potential height is introduced. Driven by a collaborative approach we call educator-developer dialogue, an updated version of the software Quantum Composer is presented. For educational purposes, we map the two lowest energy states of the 1D-Schrödinger equation to the Bloch sphere representation, leading to a rather clear and intuitive physical picture for the pertinent time dynamics.

Occupational exposure to electromagnetic fields from dental devices: A descriptive study

Abstract
 
 Objective: Electromagnetic Field sources which are widely used as part of the operating mechanism occupational exposure occurs with the electricity is generated, distributed or usage in the everyday environment. We aimed to obtain the Extremely Low Frequency-Magnetic Field exposure profile for dental health workers from electrical devices used in dentistry. 
 Methods: Measurements were performed while appliances under working conditions, 10 cm distance with the device for 6 minutes and for 7 days. The highest measured value in every 10 second was recorded. The mean ± SD of minimum and maximum Extremely Low Frequency-Magnetic Field for high-speed dental handpiece with LED, low-speed dental handpiece, model-trimming machine, automatic boil-out unit, steam machine, vacuum device, and polishing machine were recorded in milliGauss. 
 Results: The values which obtains from model-trimming machine and polishing machine were remarkable (809.17 ± 37.70 / 975.00 ± 10.27, 649.33 ± 201.37 / 1367.00 ± 32.17, respectively). Conclusion: The results show that periodic Electromagnetic Field exposure measurements should be conducted to obtain more detailed information about workplace exposures and sources.
 
 Keywords: Health, electromagnetic field, extremely low-frequency field, exposure, occupational

A novel magnetically oscillatory fluidized bed using micron-sized magnetic particles for continuous capture of emulsified oil droplets

Treatment of emulsions is frequently required for water environment protection and oil recovery. Breaking the emulsion structure and separating the emulsified oil are key stages. However, conventional emulsion separation methods suffer from high reagent and energy costs, and low batch capacity. In this study, a novel magnetically oscillatory fluidized bed (MOFB) was developed to realize cost-effective and continuously operated emulsion separation through the introduction of reusable micron-sized magnetic particles (MMPs) and a low-energy electromagnetic field. The emulsified oil droplets were continuously captured by MMPs in oscillatory motion driven by a periodic electromagnetic field. The constructed MOFB showed excellent separation efficiency at a high influent flow rate of 20 mL/min. And in the long-term operation of the MOFB, a higher treatment capacity for emulsified oil was obtained by the MMPs (11.1 g liquid paraffin oil /g MMPs) than by the commonly used nano-sized magnetic particles. The entire oil capture process by moved MMPs was confirmed via in situ observation using a high-speed camera. To further reveal the oil capture mechanisms, meshing and kinematics analyses were performed to construct an indicator termed dynamic bed voidage (εD). It was found that the value of εD could be regulated by the magnetic field strength and frequency, and a low value of εD (<30.3%) was crucial to maintain a highly efficient capture of emulsified oil droplets. This study provides insights into the design of a novel magnetic separator for continuous emulsion separation and promotes technological evolution toward economically competitive separation methods.

Nondispersive wave packets in planar helium

Two-electron wave packets found in driven planar helium follow a classical periodic orbit without spreading and are localized in nonlinear resonance islands of the classical phase space. The general mechanism that produces these nondispersive wave packets is the near-resonant coupling between highly correlated, asymmetric, and doubly excited states of the atom with an external periodic electromagnetic field. We provide a full characterization of these two-electron nondispersive wave packets found in the Floquet spectrum of driven planar helium. This includes the characteristic energy spectrum, relatively long lifetimes, and the identification of the resonance states of helium that are responsible for their formation. This is achieved with the help of an efficient quantum treatment of driven planar helium which combines Floquet theory, complex rotation, and the representation of the Hamiltonian in a set of four coupled harmonic oscillators.

Analysis of Ocean Tide‐Induced Magnetic Fields Derived From Oceanic In Situ Observations: Climate Trends and the Remarkable Sensitivity of Shelf Regions

AbstractTidal motion of oceanic salt water through the ambient geomagnetic field induces periodic electromagnetic field signals. Amplitudes of the induced signals are sensitive to variations in electrical seawater conductivity and, consequently, to changes in oceanic temperature and salinity. In this paper, we computed and analyzed time series of global ocean tide‐induced magnetic field amplitudes. For this purpose, we combined data of global in situ observations of oceanic temperature and salinity fields from 1990–2016 with data of oceanic tidal flow, the geomagnetic field, mantle conductivity, and sediment conductance to derive ocean tide‐induced magnetic field amplitudes. The results were used to compare present day developments in the oceanic climate with two existing climate model scenarios, namely, global oceanic warming and Greenland glacial melting. Model fits of linear and quadratic long‐term trends of the derived magnetic field amplitudes show indications for both scenarios. Also, we find that magnetic field amplitude anomalies caused by oceanic seasonal variability and oceanic climate variations are 10 times larger in shallow ocean regions than in the open ocean. Consequently, changes in the oceanic and therefore the Earth's climate system will be observed first in shelf regions. In other words, climate variations of ocean tide‐induced magnetic field amplitudes are best observed in shallow ocean regions using targeted monitoring techniques.

Artificially structured boundary plasma trap

A computer simulation is presented of single-species non-neutral plasma confinement using an artificially structured boundary. The artificially structured boundary produces a spatially periodic static electromagnetic field along the plasma periphery such that the spatial period of the applied field is much smaller than the dimensions of the confined plasma. The simulated non-neutral plasma self-consistently produces an electrostatic potential energy well for oppositely signed charged particles. The results support the prospect of developing plasma space-charge based confinement, with an unmagnetized plasma of one species of charged particles confined by an electric field produced by an edge-confined plasma of a second species of charged particles. The Warp particle-in-cell code is used for the simulations.

Quasi-energies of coupled qubits: Magnus-Floquet states and their probing by weak signal

The behaviour of two coupled qubits in a periodic electromagnetic field of arbitrary amplitude was investigated. Quasienergy levels of the system as a function of the driving field parameters and the qubit coupling energy were found on the basis of the Floquet theory and the Magnus approximation. It is shown that the quasienergy levels may intersect depending on the control parameters. This fact can manifest itself as appearance of the novel resonances and interesting nonlinear phenomena.

Energy dependence on modes of electric activities of neuron driven by different external mixed signals under electromagnetic induction

Energy supply and release play an important role in individual neuron and neural network. In this paper, the electrical activities and Hamilton energy of neuron are investigated when external mixed signals (i.e., the periodic stimulus current and the periodic electromagnetic field) are imposed on the neuron under the electromagnetic induction. As a result, the Hamilton energy is much dependent on the mode transition, the multiple electric activity modes and the numerical analysis of Hamilton energy are more complicated under various parameters. When the periodic high-low frequency electromagnetic radiation is imposed in neuron, it is found that the electrical activities are more complex, and the changing of energy is obvious. In addition, the response of electrical activity and Hamilton energy is much dependent on the changing of amplitude A , B when the external high-low frequency signal is imposed on the neuron, meanwhile, the energy of bursting state is lower than the one of spiking state. It can be used for investigation about the energy coding in the neuron even the neuron networks.

Time-dependent pseudofermionic systems and coherent states

We show, by means of similarity transformations, that the time-dependent fermionic systems are associated to the time-dependent pseudofermionic systems. A general construction of time dependent fermionic coherent states (FCSs) describing the two-level dissipative system driven by a periodic electromagnetic field is developed, and a strict parallelism between FCS and the time dependent pseudofermionic coherent states (PFCSs) is established and examined. We discuss properties of the constructed FCS and PFCS.

Guiding and collimating fast electron beam by the quasi-static electromagnetic field array

A guidance and collimation scheme for fast electron beam in a traverse periodic quasi-static electromagnetic field array is proposed with the semi-analytic method and the particle-in-cell simulation. The sheath electric fields on the surfaces of nanowires and the magnetic fields around the nanowires form a traverse periodic quasi-static electromagnetic field array. Therefore, most of the fast electrons are confined at the nanowire surfaces and transport forward. More importantly, due to the divergent property of the beams, the magnitudes of the generated fields decrease with the target depth. The lateral momenta of the electrons convert into the forward momenta through Lorenz force, and they cannot recover their initial values. Therefore, the fast electrons can be guided and collimated efficiently in the gaps between the nanowires. In our particle-in-cell simulations, the observed guiding efficiency exceeds 80% compared with the reference target.

Pulsar-Driven Jets in Supernovae, Gamma-Ray Bursts, and the Universe

The bipolarity of Supernova 1987A can be understood through its very early light curve from the CTIO 0.4 m telescope and IUE FES and following speckle observations of the “Mystery Spot”. These indicate a beam/jet of light/particles, with initial collimation factors &gt;104and velocities &gt;0.95 c, involving up to 10−5 M⊙interacting with circumstellar material. These can be produced by a model of pulsar emission from polarization currents induced/(modulated faster than c) beyond the pulsar light cylinder by the periodic electromagnetic field (supraluminally induced polarization currents (SLIP)). SLIP accounts for the disruption of supernova progenitors and their anomalous dimming at cosmological distances, jets from Sco X-1 and SS 433, the lack/presence of pulsations from the high-/low-luminosity low-mass X-ray binaries, and long/short gamma-ray bursts, and it predicts that their afterglows are thepulsedoptical-/near-infrared emission associated with these pulsars. SLIP may also account for the TeV e+/e−results from PAMELA and ATIC, the WMAP “Haze”/Fermi “Bubbles,” and ther-process. SLIP jets from SNe of the first stars may allow galaxies to form without dark matter and explain the peculiar nongravitational motions between pairs of distant galaxies observed by GALEX.

On the role and impact of electromagnetic fields in ecosystems

Role and effects of electromagnetic fiin living organisms and ecosystems are discussed within a nonlinear mechanism of charge transport processes that take place during respiration and photosynthesis, as well as in hydrogen-bonded chains of water molecules. Such mechanism is based on the account of the interaction between charges and induced by the distortions of macromolecules or water chains, which results in the self-trapping of charges in soliton states. It is shown that electrosolitons have some characteristic frequency, with respect to which periodic electromagnetic fi elds have resonant effect on their dynamics and stability. At certain conditions unbiased (with zero mean-value) periodic electromagnetic radiation can cause drift of solitons along molecular chains, and, therefore, affect charge transport processes. Such drift of particles in unbiased fi elds is known as ratchet phenomenon. Similar dynamics can be caused by stochastic fi elds and takes place in water chains present in interfacial water in cells, in coherence domains of water in the atmosphere and oceans. These results can explain the mechanism of impact of the electromagnetic solar activity on metabolism of living organisms and functioning of ecosystems. Moreover, it provides the mechanism for the formation of ecosystems via fi eld-mediated exchange of information between the ecosystem elements and existence of the hierarchy of ecosystems. This study also indicates a possible danger of the electromagnetic smog on ecosystems.

Convergence acceleration in the polarization method for nonlinear periodic fields

PurposeThe purpose of this paper is to present three novel techniques aimed at increasing the efficiency of the polarization fixed point method for the solution of nonlinear periodic field problems.Design/methodology/approachFirstly, the characteristic B‐M resulting from the constitutive relation B‐H is replaced by a relation between the components of the harmonics of the vectors B and M. Secondly, a dynamic overrelaxation method is implemented for the convergence acceleration of the iterative process involved. Thirdly, a modified dynamic overrelaxation method is proposed, where only the relation B‐M between the magnitudes of the field vectors is used.FindingsBy approximating the actual characteristic B‐M by the relation between the components of the harmonics of the vectors B and M, the amount of computation required for the field analysis is substantially reduced. The rate of convergence of the iterative process is increased by implementing the proposed dynamic overrelaxation technique, with the convergence being further accelerated by applying the modified dynamic overrelaxation presented. The memory space is also well reduced with respect to existent methods and accurate results for nonlinear fields in a real world structure are obtained utilizing a normal size processor notebook in a time of about one‐half of one minute when no induced currents are considered and of about one minute when eddy currents induced in solid ferromagnetic parts are also fully analyzed.Originality/valueThe originality of the novel techniques presented in the paper consists in the drastic approximations proposed for the material characteristics of the nonlinear ferromagnetic media in the analysis of periodic electromagnetic fields. These techniques are highly efficient and yield accurate numerical results.

Plasma Interaction With a Static Spatially Periodic Electromagnetic Field

Initial research on a static electromagnetic “force field” is presented. The force field consists of a planar sequence of magnetic cusps that are electrostatically plugged. Electrostatic plugging with applied potential variations that are similar to those applied to one side of a nested Penning trap allows a force field to reflect incident charged particles of either signs of charge. Experimental and computational results are reported.

Nonlinear Eddy Current Analysis by BEM Minimum Order Formulation

The eddy current induced in nonlinear material such as steel is formulated with the help of the boundary integral equations of the minimum order for the calculation of 3-D eddy current problems. The integral equations for the nonlinear analysis are derived by considering nonlinear terms as fictitious sources. Since the periodic electromagnetic fields in the steel are distorted, these fields are expressed with the help of Fourier series, whose fundamental and harmonic fields are determined by solving the corresponding integral equations with the surface magnetic fields given as the boundary values. The internal and surface electromagnetic fields are obtained numerically one after the other until convergence.

Crack movement in layered composites under electric field affect

The variation principle is applied for defining a crack in the solid body. The methods proposed in [G. Sih, C. Chen, Non-self-similar crack growth in elastic–plastic finite thickness plate, Theoretical and Applied Fracture Mechanics 3 (1985) 125–139] extend to presence of electromagnetic fields in material. Crack propagation in non-homogeneous media has been considered. It is shown that electromagnetic fields in the material are essentially affecting the trajectory. The crack trajectory stability has been studied as function of fracture energy, phase portraits of the trajectory in different media have been built, and various attractor types have been revealed. Different crack morphologies from single straight and oscillating crack propagation to straight double crack propagation were theoretically founded. In compliance with the experimental data of [R. Niefanger, V.-B. Pham, G. Schneider, H.-A. Bahr, H. Balke, U. Bahr, Quasi-static straight and oscillatory crack propagation in ferroelectric ceramics due to moving electric field: experiments and theory, Acta Materialia 52 (1) (2004) 117–127], it has been demonstrated that periodic electromagnetic field results in trajectory stochastization. This can be used for switching the crack over from the mode of mainline propagation into the mode of development of the field of diffused microcracks.

Periodic electromagnetic fields for finding the propagation constant of coaxial air lines with surface roughness and ohmic wall loss

Maxwell's equations in the context of Floquet's theorem for construction of a sequence of periodic precision air lines with surface roughness and ohmic resistance in the conductor walls offer a solution for finding the propagation constants in correspondence to the principal transverse magnetic mode. Boundary conditions to define surface roughness and ohmic wall loss through a tangent surface vector expression to incorporate composite axial and radial electromagnetic field components enable the construction of a system determinant to extract the propagation constant.

Nonlinear eddy current analysis by line integral equations utilizing integral formulas of electromagnetic fields

PurposeThe purpose of this paper is to supply a numerical analysis tool to solve eddy currents induced in nonlinear materials such as steel by boundary element method (BEM), and then apply it to design and analysis of power devices.Design/methodology/approachUtilizing integral formulas derived on the basis of rapid attenuation of the electromagnetic fields, the paper formulates eddy currents in steel. In the formulation, nonlinear terms are regarded as virtual sources, which are improved iteratively with the electromagnetic fields on the surface. The periodic electromagnetic fields are expanded in Fourier series and each harmonic is analyzed by BEM. The surface and internal electromagnetic fields are obtained numerically one after the other until convergence by the Newton‐Raphson method.FindingsIt is confirmed that this approach gives accurate solutions with meshes much larger than the skin depth and therefore is adequate to apply to a large‐scale application.Research limitations/implicationsThe eddy current is formulated by utilizing the impedance boundary condition in order to meet a large‐scale application, and so solutions near the edge are poor. In the case of better solutions being required, some modifications are necessary.Originality/valueTo lessen computer memory consumption, the parallel component of the currents to the steel surface is analyzed as a 2D problem and the normal component is obtained from the parallel component. One 2D equation for one analyzing region is discretized by dividing the region into layers adaptively and then solved. Next, another is solved sequentially. This method gives a compatible numerical analysis tool with finite element method.

Effects of Periodic Electromagnetic Field on Charge Transport in Macromolecules

We study effects of periodic fields on charge transport in macromolecules and show that solitons acquire complex dynamics induced by the interplay between the periodic in time external field, energy dissipation, and depends on the molecule symmetry. Soliton dynamics is a superposition of the oscillations of the soliton c.m.c. with the frequency of the external field and directed current. Even unbiased periodic in time fields can cause drift of solitons (the ratchet effect) in the Peierls-Nabarro periodic potential. This effect has a threshold with respect to the intensity and frequency of the field.We calculate the dependence of the amplitude of soliton oscillations and the velocity of the drift on the intensity of the field, its frequency, and energy dissipation. Thus, we show that nonlinear charge transport processes in a field which is periodic in time acquire completely different dynamics than linear processes. This clearly plays a role in metabolism of biosystems.

Complex magnetic monopoles, geometric phases and quantum evolution in the vicinity of diabolic and exceptional points

We consider the geometric phase and quantum tunneling in the vicinity of diabolic and exceptional points. We show that the geometric phase associated with the degeneracy points is defined by the flux of complex magnetic monopoles. In the limit of weak coupling, the leading contribution to the real part of the geometric phase is given by the flux of the Dirac monopole plus a quadrupole term, and the expansion of the imaginary part starts with a dipole-like field. For a two-level system governed by a generic non-Hermitian Hamiltonian, we derive a formula to compute the non-adiabatic, complex, geometric phase by integrating over the complex Bloch sphere. We apply our results to study a dissipative two-level system driven by a periodic electromagnetic field and show that, in the vicinity of the exceptional point, the complex geometric phase behaves like a step-function. Studying the tunneling process near and at the exceptional point, we find two different regimes: coherent and incoherent. The coherent regime is characterized by Rabi oscillations, with a one-sheeted hyperbolic monopole emerging in this region of the parameters. The two-sheeted hyperbolic monopole is associated with the incoherent regime. We show that the dissipation results in a series of pulses in the complex geometric phase which disappear when the dissipation dies out. Such a strong coupling effect of the environment is beyond the conventional adiabatic treatment of the Berry phase.