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[en] The thermodynamic potential of the relativistic electron-positron gas is calculated in the one-loop approximation in a homogeneous magnetic field. The calculation has been made in the imaginary-time formalism as well as in the real-time formalism. The detailed analysis has been made for the dependence of the monotonous part of the thermodynamic potential on the temperature and magnetic field strength. For the first time the exact expression is obtained for the oscillating part of the thermodynamic potential in the case of relatively weak magnetic field. 31 refs

[en] Photon splitting in a very strong magnetic field is analyzed for energy ω<2m. The amplitude obtained on the base of the operator-diagram technique is used. It is shown that in a magnetic field much higher than a critical one the splitting amplitude is independent on the field. Our calculation is in good agreement with previous results of Adler and in strong contradiction with a recent paper by Mentzel et al. copyright 1996 The American Physical Society

[en] We regularize the 3-D quantum electrodynamics by a parity invariant Pauli-Villars regularization method which is a 3-D variant of the chiral gauge invariant Pauli-Villars regularization proposed by Frolov and Slavnov and calculate the one-loop photon vacuum polarization tensor. (author)

[en] Numerically is calculated the spectral-angular distribution of the low-frequency radiation of relativistic particles moving along a circle arc. It is shown that the distribution differs essentially from the synchrotron one even in the case of radiation in a long magnet in which the angle of rotation of a particle is much quarter than a characteristic angle gamma^-1

[en] The existence of the magnetic type mixed fermion-photon condensate breaking the chiral symmetry in gauged Nambu-Jona-Lasino model is shown. The renormalization constant of the composite operator is found in the planar ladder approximation and an analytical expression for the renormalized condensate is obtained for different regions of the phase diagram

[en] The quantum theory is presented of propagation in Raman scattering of a strong laser field using space and time dependent modal operators governed by the Heisenberg-like equation involving the momentum operator and the Heisenberg equation. The quasi-distribution related to anti-normal ordering of boson operators was adopted as well as the generalized superposition of the coherent field and quantum noise. The temporal and one-dimensional spatial evolution of the photon and phonon statistics is studied, as are the quadrature variances and the mean integrated intensity of the fields, including the nonclassical ones. A different behavior of the principal squeeze variance for the compound modes can be seen, provided that all the modes are initially coherent. An effect of smoothing out was found for the spatial and temporal dependence of the photon-number distribution when the number of photons is increased. 3 figs., 20 refs

[en] The Lamb-shift corrections to the interaction Lagrangian are calculated in the framework of bilocal-field quantum electrodynamics (theory with the three fundamental constants c, h, k)

[en] The thermal self-energy of an electron in a static uniform magnetic field B is calculated to first order in the fine structure constant α and to all orders in eB. We use two methods, one based on the Furry picture and another based on Schwinger's proper-time method. As external states we consider relativistic Landau levels with special emphasis on the lowest Landau level. In the high-temperature limit we derive self-consistent dispersion relations for particle and hole excitations, showing the chiral asymmetry caused by the external field. For weak fields, earlier results on the ground-state energy and the anomalous magnetic moment are discussed and compared with the present analysis. In the strong-field limit the appearance of a field-independent imaginary part of the self-energy, related to Landau damping in the e⁺e^-plasma, is pointed out. (orig.)

[en] It was shown in the previous work (T.IEE Japan,113-A,719,(1993)) that the electron, which is in fact a structureless point particle with its self-field, behaves as if it has virtual charge distribution when it interacts with the Coulomb potential fixed in a space. In this paper, it is proved that in general the virtual charge distribution appears for the electron interacting with an arbitrary physical potential as well as the Coulomb potential. Next, we consider an electron that obeys the classical Lorentz-Dirac equation (i.e., L-D electron). We investigate the relation between the force on the charged particle and the wavelength of the electromagnetic wave in the two cases; one is the case of L-D electron, and the other an extended charge of classical electron radius. We see that L-D electron is more similar to the extended charged particle than the structureless electron. So we can find some virtual structure. As a result, we conclude the equivalence of the point electron with its self-field and the charged particle having a virtual charge distribution. (author)