Total conversion of the polarization of electromagnetic waves during excitation of cyclotron polaritons in a two-dimensional electron system

The reflection of an electromagnetic wave from a two-dimensional (2D) electron system in a magnetic field is studied. It is predicted that a p (s) polarized incident wave will be totally converted into a reflected wave with the orthogonal polarization when cyclotron polaritons are excited in the 2D system. For a high electron density in the 2D system, the effect remains very substantial in magnitude even in the presence of electron scattering. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 4, 247–252 (25 August 1999)     

Electromagnetic wave scattering by large-scale inhomogeneities in a bragg cavity

We study the single scattering of a plane electromagnetic wave by random inhomogeneities in a plane periodically nonuniform layer with a reflecting rear boundary. It is shown that when the incident wave satisfies the condition of excitation of the fundamental Bragg cavity mode and its field is large in the layer depth, the average angular spectrum of the backscattered wave field at the cavity output has a narrow maximum proportional to the exponent of the quadruple optical thickness of the periodic structure. This maximum corresponds to the condition of excitation of the fundamental Bragg cavity mode by the scattered field. The other spectral maxima have small amplitudes and intensities. Such scattering takes place if the characteristic size of random inhomogeneities in the direction perpendicular to the layer boundary exceeds the scale of multiple scattering on a periodic structure. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 11, pp. 1342–1354, November, 1997.     

Effect of a rapid increase in the strength of the gravitational field on the propagation of electromagnetic radiation

This article examines the shift in the frequency of an electromagnetic wave as it passes through a region of space in which the strength of the gravitational field increases rapidly. It is shown that charge or current in a region of space with a variable gravitational field radiates electromagnetic waves. Russian Federal Nuclear Center—VNIIEF. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 31–34, March, 1997.     

The exact behavior of electromagnetic Faraday rotation in crossing a gravitational sandwich wave in general relativity

We have analyzed the exact behavior of the polarization vector of a linearly polarized electromagnetic shock wave upon crossing a gravitational sandwich wave, by using Einstein's theory of general relativity. The Faraday rotation in the polarization vector of the electromagnetic field is induced in this nonlinear process. We show that the Faraday's angle highly depends on the electromagnetic parameter, gravitational parameter and the width of the gravitational sandwich wave.     

Propagation of a beam of gamma rays in the field of a monochromatic laser wave

The head-on propagation of a beam of γ grays through the field of a laser wave is investigated. The optical properties of the laser wave (as a medium) are described by the dielectric tensor. The refractive indices are determined, and the polarization characteristics of electromagnetic normal modes capable of propagating in such a medium are investigated. Relations are derived to describe the variation of the initial polarization and intensity of a γ-ray beam as it propagates in a laser field. The influence of laser intensity on the investigated process is discussed. Zh. éksp. Teor. Fiz. 112, 2016–2029 (December 1997)     

Double stimulated mandelstam-brillouin scattering of electromagnetic waves of arbitrary polarization in an isotropic plasma

We study the nonlinear interaction of a system of incident and reflected electromagnetic waves of arbitrary polarization, propagating in a quasihomogeneous plane layer of isotropic plasma obliquely to the boundary, with scattered electromagnetic waves. These waves are coupled in the double stimulated Mandelstam-Brillouin scattering by a common sound wave that is parallel to the layer boundary. We examine the influence of the wave polarization on the threshold intensity, instability growth rate, and characteristics of the stationary solution. It is found that the nonlinear interaction scales are different for waves of different polarization. In particular, this leads to a change of the wave polarization in the course of the interaction. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 7, pp. 851–859, July, 1997.     

Fabry-Perot cavity in the field of a gravitational wave

The structure of the electromagnetic field inside a laser cavity—a gravitational-wave detector—is studied. The properties of the spatial and temporal phases of the standing electromagnetic wave are discussed in detail and the corrections appearing in the electric field of the wave as a result of the action of gravitational radiation on the optical system are determined. Zh. éksp. Teor. Fiz. 113, 398–408 (February 1998)     

Spinor Relativity

Spinor relativity is a unified field theory, which derives gravitational and electromagnetic fields as well as a spinor field from the geometry of an eight-dimensional complex and ‘chiral’ manifold. The structure of the theory is analogous to that of general relativity: it is based on a metric with invariance group GL(ℂ²), which combines the Lorentz group with electromagnetic U(1), and the dynamics is determined by an action, which is an integral of a curvature scalar and does not contain coupling constants. The theory is related to physics on spacetime by the assumption of a symmetry-breaking ground state such that a four-dimensional submanifold with classical properties arises. In the vicinity of the ground state, the scale of which is of Planck order, the equation system of spinor relativity reduces to the usual Einstein and Maxwell equations describing gravitational and electromagnetic fields coupled to a Dirac spinor field, which satisfies a non-linear equation; an additional equation relates the electromagnetic field to the polarization of the ground state condensate.     

Probing for new physics and detecting non-linear vacuum QED effects using gravitational wave interferometer antennas

Low energy non-linear QED effects in vacuum have been predicted since 1936 and have been subject of research for many decades. Two main schemes have been proposed for such a ‘first’ detection: measurements of ellipticity acquired by a linearly polarized beam of light passing through a magnetic field and direct light–light scattering. The study of the propagation of light through an external field can also be used to probe for new physics such as the existence of axion-like particles and millicharged particles. Their existence in nature would cause the index of refraction of vacuum to be different from unity in the presence of an external field and dependent of the polarization direction of the propagating light. The major achievement of reaching the project sensitivities in gravitational wave interferometers such as LIGO and VIRGO has opened the possibility of using such instruments for the detection of QED corrections in electrodynamics and for probing new physics at very low energies. We show that it is possible to distinguish between various scenarios of new physics in the hypothetical case of detecting unexpected values. Considering the design sensitivity in the strain of the near future VIRGO+ interferometer leads to a variable dipole magnet configuration such that B ² D≥13000 T² m  for a ‘first’ vacuum non-linear QED detection.     

One-dimensional finite motion of a particle in the field of a weak gravitational wave

The Hamiltonian formalism of classical mechanics can be used effectively to describe the motion of a particle (including a massless one) along a segment of material that is in a nonsteady gravitational field. The problem of applying this formalism to the detection of gravitational waves using a Michelson or Fabry—Perot interferometer is considered. The existence of a phase shift of an electromagnetic wave due to the interaction of the electromagnetic and gravitational fields is noted. Moscow State Aviation Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 13–17, August, 1997.     

Non-Existence of Black Hole Solutions¶for a Spherically Symmetric, Static Einstein–Dirac–Maxwell System

We consider for j=?, … a spherically symmetric, static system of (2j+1) Dirac particles, each having total angular momentum j. The Dirac particles interact via a classical gravitational and electromagnetic field. The Einstein–Dirac–Maxwell equations for this system are derived. It is shown that, under weak regularity conditions on the form of the horizon, the only black hole solutions of the EDM equations are the Reissner–Nordstr?m solutions. In other words, the spinors must vanish identically. Applied to the gravitational collapse of a “cloud” of spin-?-particles to a black hole, our result indicates that the Dirac particles must eventually disappear inside the event horizon. Received: 2 November 1998 / Accepted: 23 February 1999     

Test of a model coupling of electromagnetic and gravitational fields by using high-frequency gravitational waves

Models of the coupling of electromagnetic and gravitational fields have been studied extensively for many years. In this paper,we consider the coupling between the Maxwell field and the Weyl tensor of the gravitational field to study how the wavevector of the electromagnetic wave is affected by a plane gravitational wave. We find that the wavevector depends upon the frequency and direction of polarization of the electromagnetic waves, the parameter that couples the Maxwell field and the Weyl tensor, and the angle between the direction of propagation of the electromagnetic wave and the coordinate axis. The results show that this coupling model can be tested by the detection of high-frequency gravitational waves.     

New intensity magneto-optical effect in materials exhibiting giant magnetoresistance

The change in the reflectivity of a metallic magnetic multilayer that exhibits giant magnetoresistance for a monochromatic electromagnetic plane wave with polarization along the magnetization (s polarization) in response to a change from the antiferromagnetic magnetic configuration of the multilayer to the ferromagnetic configuration is investigated. This magneto-optical effect is treated in the effective-medium approximation, in which the dielectric constant needed is found analytically with consideration of the interface roughness scattering of electrons. It is shown in the example of an Fe/Cu multilayer that the effect amounts to ∼0.7%. The representation found for the complex conductivity is convenient in a special case for investigating the magnetoresistive effect. Zh. éksp. Teor. Fiz. 114, 1101–1114 (September 1998)     

Polarization-interference effects in the bremsstrahlung of quasiclassical electrons on ions with a core

The polarization dependence of the stimulated bremsstrahlung and inverse bremsstrahlung (SBIB) of quasiclassical electrons on highly charged ions with a core is calculated in the approximation of a specified Coulomb current. Emission frequencies close to an eigenfrequency of the ion core are considered. The contributions of the static and polarization channels are taken into account in the amplitude of the process. When the nondipole nature of the interaction between the incident particle and a resonant transition in the ion core is taken into account, interference between these channels causes the spectral-amplitude characteristics of the process to assume a specific dependence on the angle α between the electric field intensity vector of the electromagnetic wave and the initial velocity vector of the incident particle. This dependence, which persists after integration of the cross section over the scattering angle of the incident particle, causes interference effects, viz., asymmetry of the line shape and dips in the dependence of the SBIB cross section on electric field intensity, to appear for α=π/2 and significantly reduces them for α=0. Zh. éksp. Teor. Fiz. 115, 1619–1629 (May 1999)     

Non-minimal Maxwell-modified Gauss–Bonnet cosmologies: inflation and dark energy

In this paper we show that power-law inflation can be realized in non-minimal gravitational coupling of electromagnetic field with a general function of the Gauss–Bonnet invariant. Such a non-minimal coupling may appear due to quantum corrections. We also consider modified Maxwell-F(G) gravity in which non-minimal coupling between electromagnetic field and f(G) occurs in the framework of modified Gauss–Bonnet gravity. It is shown that inflationary cosmology and late-time accelerated expansion of the universe are possible in such a theory.     

Gravity induced particle production in earth’s gravitational field in TeV region

We discuss the production of particles via interaction with the earth’s gravitational field. Explicit calculations are done for high energy scalars passing through earth’s gravitational field. We show for example, that the width for the scalar processφ→3φ can become comparable with a typical weak decay width at an energy scale of a few TeV. (Similar conclusions can be drawn about particles that ultimately couple to some scalar field.) We speculate that similar processes may be responsible for many of the anomalies in the 10–10⁴ TeV experimental data.     

Solution of Maxwell’s equations on a de Sitter background

The Maxwell equations for the electromagnetic potential, supplemented by the Lorenz gauge condition, are decoupled and solved exactly in de Sitter space–time studied in static spherical coordinates. There is no source besides the background. One component of the vector field is expressed, in its radial part, through the solution of a fourth-order ordinary differential equation obeying given initial conditions. The other components of the vector field are then found by acting with lower-order differential operators on the solution of the fourth-order equation (while the transverse part is decoupled and solved exactly from the beginning). The whole four-vector potential is eventually expressed through hypergeometric functions and spherical harmonics. Its radial part is plotted for given choices of initial conditions. We have thus completely succeeded in solving the homogeneous vector wave equation for Maxwell theory in the Lorenz gauge when a de Sitter space–time is considered, which is relevant both for inflationary cosmology and gravitational wave theory. The decoupling technique and analytic formulae and plots are completely original. This is an important step towards solving exactly the tensor wave equation in de Sitter space–time, which has important applications to the theory of gravitational waves about curved backgrounds.     

Squeezed harmonic generation in cooperative resonance scattering of intense radiation by dipole molecules

We examine the processes of resonance Raman scattering of intense electromagnetic radiation by a lumped system of two-level atoms with a constant dipole moment. We calculate the intensity of the sth generated harmonic in a saturating electromagnetic field and the statistical characteristics of this harmonic. Finally, we show that the sth harmonic is squeezed at saturating field intensities. Zh. éksp. Teor. Fiz. 113, 1206–1212 (April 1998)     

Effect of anisotropy of a medium on the scattering of electromagnetic waves by a subsurface inclusion

We have constructed a physicomathematical model of scattering of electromagnetic waves by a homogeneous object immersed in a material halfspace, which allows for anisotropy of electromagnetic properties of the scatterer and surrounding medium. This model is motivated by the need for remote sensing, nondestructive testing, and microwave devices and is based on the numerical solution of a system of integral equations for the electric field components inside an inclusion using the method of moments. We present numerical examples that illustrate wave scattering by an inhomogeneity in sea ice and polymer composite. State University, Khar’kov, Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 10, pp. 1249–1259, October, 1997.     

Spectral Analysis for Systems of Atoms and Molecules Coupled to the Quantized Radiation Field

We consider systems of static nuclei and electrons – atoms and molecules – coupled to the quantized radiation field. The interactions between electrons and the soft modes of the quantized electromagnetic field are described by minimal coupling, p→p−e A (x), where A(x) is the electromagnetic vector potential with an ultraviolet cutoff. If the interactions between the electrons and the quantized radiation field are turned off, the atom or molecule is assumed to have at least one bound state. We prove that, for sufficiently small values of the fine structure constant α, the interacting system has a ground state corresponding to the bottom of its energy spectrum. For an atom, we prove that its excited states above the ground state turn into metastable states whose life-times we estimate. Furthermore the energy spectrum is absolutely continuous, except, perhaps, in a small interval above the ground state energy and around the threshold energies of the atom or molecule. Received: 3 September 1998 / Accepted: 17 March 1999