Electromagnetic Angular Momentum Research Articles

Realization of Flat-Topped Electromagnetic Orbital Angular Momentum Vortex Wave With a Square Array

Realization of Flat-Topped Electromagnetic Orbital Angular Momentum Vortex Wave With a Square Array

Numerical Simulation of Radiative Transfer of Electromagnetic Angular Momentum

Numerical Simulation of Radiative Transfer of Electromagnetic Angular Momentum

On magnetic monopole and Dirac quantization condition in the minimal length formalism

In this article, we study the effects of minimal length corrections on the cyclotron acceleration and radiation of a charged particle moving in a magnetic monopole field. Using the modified Hamiltonian describing the dynamics of a charged particle moving in a magnetic monopole field, we derive the modified cyclotron frequency and modified acceleration. Also, we derive the modified power for the cyclotron radiation using the modified acceleration. We find that all modified quantities are dependent on the deformation parameter α. In addition, we find that the modified electromagnetic angular momentum and magnetic charges are not quantized as an integer multiple; thus, we establish that the modified Dirac quantization condition and the usual Dirac quantization condition is just the term of zero order in α. The modified Dirac quantization condition allows fractional charges that arise from vacuum fluctuations. In the Born approximation, we derive the modified scattering cross-section and then we estimate the upper bound on the minimal length.

Ergomagnetosphere, ejection disc, magnetopause in M87 – I. Global flow of mass, angular momentum, energy, and current

ABSTRACT We interpret the 1.3 mm VLBI observations made by the Event Horizon Telescope of the black hole in M87. It is proposed that, instead of being a torus of accreting gas, the observed annular ring is a rotating, magnetically dominated ergomagnetosphere that can transmit electromagnetic angular momentum and energy outward to the disc through a combination of large scale magnetic torque and small scale instabilities. It is further proposed that energy may be extracted by magnetic flux threading the ergosphere through the efficient emission of long wavelength electromagnetic disturbances on to negative energy orbits, after the invariant B2 − E2 approaches zero on small scales. In this way, the spinning black hole and its ergosphere not only power the jets but also the ejection disc so as to drive away most of the gas supplied near the Bondi radius. This outflow takes the form of an MHD wind, extending over many decades of radius, with a unidirectional magnetic field, that is collimated by the infalling gas across a magnetopause. This wind, in turn, collimates the relativistic jets and the emission observed from the jet sheath may be associated with a return current. A model for the global flow of mass, angular momentum, energy, and current, on scales from the horizon to the Bondi radius, is outlined and discussed.

Low Sidelobe Orbital Angular Momentum Vortex Beams Based on Modified Bayliss Synthesis Method for Circular Array

Electromagnetic orbital angular momentum (OAM) vortex beam patterns generated by conventional methods are always of high sidelobe level, which severely limits its application. Considering the sidelobe suppression abilities of Bayliss synthesis method for difference beams, we present a modified Bayliss synthesis procedure to obtain low sidelobe OAM vortex beams. The Bayliss synthesis method cannot suppress the sidelobe level of difference pattern to the desired value when the element number of linear array is relatively small. By modifying the original zero locations that need to be removed in Bayliss pattern, we can further suppress the sidelobe level of difference pattern. This can be called the modified Bayliss pattern. Finally, by expanding the proposed synthesis method from linear source to circular array, theoretical results show that sidelobe levels of OAM beams can be suppressed to less than −30 dB when OAM mode number varies from <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">l</i> = 1 to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">l</i> = 10. The proposed low sidelobe OAM vortex beam can be applied in antijamming communications of near-field in the future.

Electromagnetic scoot

Recent work on scattering of massive bodies in general relativity has revealed that the mechanical center of mass of the system (or, more precisely, its relativistic mass moment) undergoes a shift during the scattering process. We show that the same phenomenon occurs in classical scattering of charged particles in flat spacetime and study the effect in detail. Working to leading order in the interaction, we derive formulas for the initial and final values of the mechanical and electromagnetic energy, momentum, angular momentum, and mass moment. We demonstrate that the change in the mechanical mass moment is balanced by an opposite change in the mass moment stored in the electromagnetic field. This is a nonradiative exchange between particles and field, analogous to the exchange of kinetic and potential energy. A simple mechanical analogy is a person scooting forward on the floor, who exchanges mass moment with the floor. We therefore say that electromagnetic scattering results in an electromagnetic scoot.

Optical topological lattices of Bloch-type skyrmion and meron topologies

Optical skyrmions, quasiparticles that are characterized by the topologically nontrivial vectorial textures of optical parameters such as the electromagnetic field, Stokes parameters, and spin angular momentum, have aroused great attention recently. New dimensions for optical information processing, transfer, and storage have become possible, and developing multiple schemes for manipulating the topological states of skyrmions, thus, is urgent. Here we propose an approach toward achieving dynamic modulation of skyrmions via changing the field symmetry and adding chirality. We demonstrate that field symmetry governs the skyrmionic transformation between skyrmions and merons, whereas material chirality modulates the twist degree of fields and spins and takes control of the Néel-type–Bloch-type skyrmionic transition. Remarkably, the enantioselective twist of skyrmions and merons results from the longitudinal spin arising from the chirality-induced splitting of the hyperboloid in the momentum space. Our investigation, therefore, acts to enrich the portfolio of optical quasiparticles. The chiral route to topological state transitions will deepen our understanding of light–matter interaction and pave the way for chiral sensing, optical tweezers, and topological phase transitions in quantum matter.

Topology, nonlocality and duality in classical electrodynamics

We have recently (Heras et al. in Eur. Phys. J. Plus 136:847, 2021) argued that classical electrodynamics can predict nonlocal effects by showing an example of a topological and nonlocal electromagnetic angular momentum. In this paper, we discuss the dual of this angular momentum which is also topological and nonlocal. We then unify both angular momenta by means of the electromagnetic angular momentum arising in the configuration formed by a dyon encircling an infinitely long dual solenoid enclosing uniform electric and magnetic fluxes and show that this electromagnetic angular momentum is topological because it depends on a winding number, is nonlocal because the electric and magnetic fields of this dual solenoid act on the dyon in regions for which these fields are excluded and is invariant under electromagnetic duality transformations. We explicitly verify that this duality-invariant electromagnetic angular momentum is insensitive to the radiative effects of the Liénard–Wiechert fields of the encircling dyon. We also show how duality symmetry of this angular momentum suggests different physical interpretations for the corresponding angular momenta that it unifies.

Can classical electrodynamics predict nonlocal effects?

Classical electrodynamics is a local theory describing local interactions between charges and electromagnetic fields and therefore one would not expect that this theory could predict nonlocal effects. But this perception implicitly assumes that the electromagnetic configurations lie in simply connected regions. In this paper, we consider an electromagnetic configuration lying in a non-simply connected region, which consists of a charged particle encircling an infinitely long solenoid enclosing a uniform magnetic flux, and show that the electromagnetic angular momentum of this configuration describes a nonlocal interaction between the encircling charge outside the solenoid and the magnetic flux confined inside the solenoid. We argue that the nonlocality of this interaction is of topological nature by showing that the electromagnetic angular momentum of the configuration is proportional to a winding number. The magnitude of this electromagnetic angular momentum may be interpreted as the classical counterpart of the Aharonov–Bohm phase.

Berry phase of the linearly polarized light wave along an optical fiber and its electromagnetic curves via quasi adapted frame

We review the geometric evolution of a linearly polarized light wave coupling into an optical fiber and the rotation of the polarization plane in a three dimensional ordinary space. We demonstrate that the evolution of a linearly polarized light wave is associated with the Berry phase or the geometric phase. We define other Fermi-Walker parallel transportation laws and connect them with the famous Rytov parallel transportation law for an electric field , which is considered as the direction of the state of the linearly polarized light wave in the optical fiber in the 3D space. Later, we define a special class of magnetic curves called by quasi electromagnetic curves (-curves), which are generated by the electric field along the linearly polarized monochromatic light wave propagating in the optical fiber. In this way, not only we define a special class of linearly polarized point-particles corresponding to -curves of the electromagnetic field along with the optical fiber in the 3D space, but we also calculate, both numerically and analytically, the electromagnetic force, Poynting vector, energy-exchanges rate, optical angular and linear momentum, and optical magnetic-torque experienced by the linearly polarizable point-particles along with the optical fiber in the 3D space.

Photon Hall Pinwheel Radiation of Angular Momentum by a Diffusing Magneto-Optical Medium.

We present a new optical effect that exchanges angular momentum between light and matter. The matter consists of an optically thick spherical, rigid agglomerate of magneto-optical scatterers placed in a homogeneous magnetic field. The light comes from an unpolarized, coherent central light source. The photon Hall effect induces a spiraling Poynting vector, both inside and outside the medium. Optical orbital angular momentum leaks out and induces a torque proportional to the injection power of the source and the photon Hall angle.

Relativistic Heisenberg principle for vortices of light from Planck to Hubble scales

We discuss, in the relativistic limits, Heisenberg's uncertainty principle for the electromagnetic orbital angular momentum (OAM) of monochromatic fields. The Landau and Peierls relativistic approa ...

Design of a Multimode OAM Vortex Electromagnetic Microstrip Array Antenna

On the basis of the characteristics of electromagnetic wave orbital angular momentum can improve spectrum efficiency, this paper proposes a low profile, more OAM models design of antenna. The antenna subject selection is made of glass fiber epoxy resin substrate, using phased array feed technology under the condition of the limited antenna unit number achieved by each antenna feed different phase excitation. By adjusting the position of the feeding point, the matching of the input impedance of the antenna is improved and the optimal structure of the antenna is determined. The simulation results show that the antenna achieves good impedance matching at the center frequency of 2.45GHz and generates 7 kinds of vortex electromagnetic beams with different OAM modes. The antenna has the characteristics of small size, light weight and low profile, which provides a novel antenna structure for the design of communication terminal antenna array.

Quantization of electromagnetic modes and angular momentum on plasmonic nanowires**Project supported by the National Natural Science Foundation of China (Grant Nos. 11704058 and 11974069), the National Special Support Program for High-level Personnel Recruitment, China (Grant No. W03020231), Liaoning Revitalization Talents Program, China (Grant No. XLYC1902113), Program for Liaoning Innovation Team in University, China (Grant No. LT2016011), Science and Technique Foundation

Quantum theory of surface plasmons is very important for studying the interactions between light and different metal nanostructures in nanoplasmonics. In this work, using the canonical quantization method, the SPPs on nanowires and their orbital and spin angular momentums are investigated. The results show that the SPPs on nanowire carry both orbital and spin momentums during propagation. Later, the result is applied to the plasmonic nanowire waveguide to show the agreement of the theory. The study is helpful for the nano wire based plasmonic interactions and the quantum information based optical circuit in the future.

Angular Momentum of the Convective Electromagnetic Field of Relativistic Charged Particles

The electromagnetic angular momentum created by the convective fields of electrically charged relativistic particles in the immediate vicinity of the charges, where these fields exceed the fields of the purely electromagnetic radiation, is considered.

Electromagnetic curves of the polarized light wave along the optical fiber in De-Sitter 2-space $${\mathbb{S}}_{1}^{2}$$

We review the geometric evolution of a linearly polarized light wave coupling into an optical fiber and the rotation of the polarization plane in De-Sitter 2-space. The optical fiber is assumed to be a one-dimensional object imbedded in the De-Sitter 2-space $${\mathbb{S}} _{1}^{2}$$ along with the paper. Mathematically, De-Sitter 2-space $${\mathbb{S}}_{1}^{2}$$ is described to be a 2-sphere in a Lorentzian space with positive curvature. Thus, in the De-Sitter 2-space, we have demonstrated that the evolution of a linearly polarized light wave is associated with the Berry phase or more commonly known as the geometric phase. The ordinary condition for parallel transportation is defined by the Fermi–Walker parallelism law. We define other Fermi–Walker parallel transportation laws and connect them with the famous Rytov parallel transportation law for an electric field $${\mathcal{E}}$$ , which is considered as the direction of the state of the linearly polarized light wave traveling through the optical fiber in De-Sitter 2-space. Later, we have defined a special class of magnetic curves called by Lorentzian spherical electromagnetic curves ( $${\mathcal{LSEM}}$$ curves), which are generated by the electric field $${\mathcal{E}}$$ along with the linearly polarized monochromatic light wave propagating in the optical fiber. In this way, not only we are able to define a special class of linearly polarized point particles corresponding to $${\mathcal{LSEM}}$$ -curves of the electromagnetic field along with the optical fiber in the De-Sitter 2-space, but we can also calculate, both numerically and analytically, the electromagnetic force, Poynting vector, energy-exchanges rate, optical angular and linear momentum, and optical magnetic torque experienced by the linearly polarizable point particles along with the optical fiber in the De-Sitter 2-space.

Angular momentum properties of hybrid cylindrical vector vortex beams in tightly focused optical systems.

Optical angular momenta (AM) have attracted tremendous research interest in recent years. In this paper we theoretically investigate the electromagnetic field and angular momentum properties of tightly focused arbitrary cylindrical vortex vector (CVV) input beams. An absorptive particle is placed in focused CVV fields to analyze the optical torques. The spin-orbit motions of the particle can be predicted and controlled when the influences of different parameters, such as the topological charge, the polarization and the initial phases, are taken into account. These findings will be helpful in optical beam shaping, optical spin-orbit interaction and practical optical manipulation.

Electromagnetic curves of the linearly polarized light wave along an optical fiber in a 3D Riemannian manifold with Bishop equations

We review the geometric evolution of a linearly polarized light wave coupling into an optical fiber and the rotation of the polarization plane in a three-dimensional (3D) Riemannian manifold. The optical fiber is assumed to be a one-dimensional object imbedded in the 3D Riemannian manifold along the paper. Thus, in the 3D Riemannian manifold, we demonstrate that the evolution of a linearly polarized light wave is associated with the Berry phase or more commonly known as the geometric phase. The ordinary condition for parallel transportation is defined by the Fermi–Walker parallelism law. We define other Fermi–Walker parallel transportation laws and connect them with the famous Rytov parallel transportation law for an electric field E, which is considered as the direction of the state of the linearly polarized light wave in the optical fiber in the 3D Riemannian manifold. Later, we define a special class of magnetic curves called by Bishop electromagnetic curves (BEM-curves), which are generated by the electric field E along the linearly polarized monochromatic light wave propagating in the optical fiber. In this way, not only we define a special class of linearly polarized point-particles corresponding to BEM-curves of the electromagnetic field along with the optical fiber in the 3D Riemannian manifold, but we also calculate, both numerically and analytically, the electromagnetic force, Poynting vector, energy-exchanges rate, optical angular and linear momentum, and optical magnetic-torque experienced by the linearly polarizable point-particles along with the optical fiber in the 3D Riemannian manifold.

New derivation of the spin of the Electromagnetic field

A new derivation of the electromagnetic field spin angular momentum is introduced. The conservation of the spin angular momentum is found to be connected with the orthogonality property of the electromagnetic field. The equation representing this conservation is found to be gauge and Lorentz invariant. A more general spin form is found that is invariant under the Heaviside–Larmor symmetry. Dual (symmetrized) Maxwell's equations are derived. It then shown that the correct form of spin angular momentum is a consequence of the symmetrized Maxwell's equations.

Electromagnetic curves of the linearly polarized light wave along an optical fiber in a 3D semi-Riemannian manifold

ABSTRACTWe review the geometric evolution of a linearly polarized light wave coupling into an optical fiber and the rotation of the polarization plane in the three dimensional semi-Riemannian manifold. The optical fiber is assumed to be a one-dimensional object imbedded in a 3D semi-Riemannian manifold along the paper. Thus, in the 3D semi-Riemannian manifold, we demonstrate that the evolution of a linearly polarized light wave is associated with the Berry phase or more commonly known as the geometric phase. The ordinary condition for parallel transportation is defined by the Fermi-Walker parallelism law. We define other Fermi-Walker parallel transportation laws and connect them with the famous Rytov parallel transportation law for an electric field , which is considered as the direction of the state of the linearly polarized light wave in the optical fiber in the 3D semi-Riemannian manifold. Later, we define a special class of magnetic curves called by Bishop electromagnetic curves (–curves), which are generated by the electric field along the linearly polarized monochromatic light wave propagating in the optical fiber. In this way, not only we define a special class of linearly polarized point-particles corresponding to –curves of the electromagnetic field along with the optical fiber in the 3D semi-Riemannian manifold, but we also calculate, both numerically and analytically, the electromagnetic force, Poynting vector, energy-exchanges rate, optical angular and linear momentum, and optical magnetic-torque experienced by the linearly polarizable point-particles along with the optical fiber in the 3D semi-Riemannian manifold.