Kerr-Schild-Vaidya fields with axial symmetry

This paper contains the Kerr-Schild-Vaidya fields with axial symmetry (all metric functions independent of Vaidya's coordinate) in closed form. The general problem of Kerr-Schild pure radiation fields without any symmetry can be reduced to a single partial differential equation by means of Kerr's theorem.     

Volume capture of ultrarelativistic electrons in the axial channeling regime

Using computer simulation the volume capture effect of ultrarelativistic electrons in the axial channeling regime in crystals is investigated. The thickness, temperature and orientational dependences of the beam fraction captured in the channeling regime in the volume of the crystal are obtained.     

Higher spin fields with mixed symmetry

Gauge invariant and gauge fixed BRS invariant actions are constructed in arbitrary dimensions for free massless integer spin fields carrying mixed representations of the Lorentz group described by Young tableaux (2, 1, 1, …, 1)_n. The complete ghost spectrum is deduced by demanding nilpotency of the BRS transformations and leads to a correct count of the on-shell degrees of freedom. Dimensional reduction is used to study the corresponding gauge invariant massive theory. On-shell consistency is then ensured by the fact that the masses arise via a “telescopic Higgs effect”.     

Anomalous passage of ultrarelativistic electrons in thick single crystals in axial channeling

The dynamics of ultrarelativistic axially channeled electrons in thick crystals is studied. It is revealed that a certain fraction of initial electrons have anomalously large dechanneling depths. It is shown also that the dechanneling depth in heavy and light crystals are comparable. In some cases, the number of channeled electrons can strongly increase at the expence of quasi-channeled electrons.

The problem of quasichanneling is also considered.     

Zero-mass scalar and electrostatic fields with the central symmetry in the general relativity

All asymptotically flat space solutions of Einstein equations with energy-momentum tensor of electrostatic and zero-mass scalar static central symmetric fields as a source were found. There are five branches of general solution; only two of them are contained in previous Penney's solution. In a limit of pure electrostatic field and pure scalar field our solutions become identical with corresponding solutions known previously.     

The axial anomaly for spin 32 fields

The axial anomaly for a Majorana spin $\text{3}\text{2}$ loop with external gravitons in supergravity is ?_μJ^μ₅ = (192π²)^??^αβ?σR?σ^μνRμναβ. This is twice the value of the corresponding anomaly for a Dirac spin $\text{1}\text{2}$ loop.     

Generation of electromagnetic waves by relativistic electrons in a cavity with crossed radial electrostatic and axial magnetic fields under plasma resonance conditions

A theoretical analysis is made of the conditions for generation of electromagnetic waves by a thin cylindrical layer of relativistic electrons rotating in crossed axial magnetic and radial electrostatic fields in a cylindrical cavity. A dispersion equation is obtained to describe the interaction between waves and electrons under plasma resonance conditions. The dependence of the growth rates on the relativistic factor and the magnetic field are studied. Zh. Tekh. Fiz. 69, 112–114 (June 1999)     

Behavior of a neutral particle with spin in an axial magnetic field

The behavior of a neutral particle with an intrinsic magnetic moment in an axisymmetric constant magnetic field is considered. The trajectory of the particle is found and the dynamics of the spin polarization vector in this field is found.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 70–72, July, 1982.The authors thank V. G. Bagrov and V. A. Bordovitsyn for discussion of the results and useful remarks.     

Behavior of electron spin in an external axisymmetric electrostatic field

The self-orientation of the spin of an ultrarelativistic electron in an external axisymmetric focusing electrostatic field is investigated qualitatively. The conditions under which a collective phenomenon of this kind occurs and its nature are clarifiedTranslated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 14–17, February, 1991.     

轴对称非静态轴外无源场的一种计算方法

利用麦克斯韦方程组和轴对称性,给出了由对称轴上的场计算非静态轴外无源场的一种方法．     

Effective method of calculating fields in optical cavities with cylindrical symmetry and shaded axial zone

It is proposed to calculate (in the diffraction approximation) fields in optical cavities with shaded axial zone and large mirror aperture, in a cylindrical coordinate frame, using a new algorithm based on the use of the stationaryphase method. Unlike the already known ones, the method has high efficiency in the region of large Fresnel numbers, and is close in speed to the method of fast Fourier transformation. The procedure is described and specific calculation results that illustrate the proposed method are presented.Translated from Preprint FIAN 121, Lebedev Physics Institute, Moscow, 1990.     

The X-ray radiation of ultrarelativistic electrons in a crystal

The properties of the coherent X-ray radiation of the ultrarelativistic electrons in a crystal are considered. The total number of X-ray and resonant γ-ray quantum emitted in a crystal under diffraction conditions are calculated.     

Replica symmetry breaking transition of the weakly anisotropic Heisenberg spin glass in magnetic fields

The spin and the chirality orderings of the three-dimensional Heisenberg spin glass with the weak random anisotropy are studied under applied magnetic fields by equilibrium Monte Carlo simulations. A replica symmetry breaking transition occurs in the chiral sector accompanied by the simultaneous spin-glass order. The ordering behavior differs significantly from that of the Ising spin glass, despite the similarity in the global symmetry. Our observation is consistent with the spin-chirality decoupling-recoupling scenario of a spin-glass transition.     

Multi-band pairing of ultrarelativistic electrons and holes in graphene bilayer

Multi-band pairing of effectively ultrarelativistic electrons and holes in asymmetrically biased graphene bilayer in strong coupling regime is considered. In this regime, the pairing affects both conduction and valence bands of the both graphene layers, and the order parameter is a matrix, which indices correspond to the bands. For band-diagonal s-wave pairing, we derive the system of multi-band gap equations for the gaps in the valence and conduction bands and solve it in the approximation of constant gaps and in the approximation of separable pairing potential. For a characteristic width of the pairing region of order of magnitude of the chemical potential, the gap values are not much different from single-band BCS estimations. However, if the pairing region is wider, then the gaps can be much larger and depend exponentially on its energy width. We also predict gapped and soliton-like oscillations of a relative phase of the gaps and unpairing of quarter-vortices at Kosterlitz-Thouless transition.     

Electromagnetic fields with symmetry

In this paper, a study of the connected subgroups of the Poincaré group which can be seen as invariance groups of electromagnetic fields (they will be called CEPS) and of their corresponding invariant fields is reported.It appears that the dimension of such symmetry groups is less than or equal to six. A method of determination of fields invariant under a Poincaré subgroup is proposed and applied to the characterization of all the electromagnetic fields invariant under each six- and five-dimensional CEPS. Moreover, it can be shown that each connected Poincaré subgroup of dimension less than or equal to four is either a CEPS or a subgroup of a CEPS.     

Orientation effects accompanying the propagation of ultrarelativistic electrons through crystals

The results obtained by experimentally investigating the dynamics of the propagation of 1.2-GeV electrons through a thin silicon single crystal are discussed. The orientation dependences of electron scattering into a small solid angle, which are measured at various scattering angles, under conditions where the effects of crystallographic axes and planes manifest themselves are interpreted. It is shown that there are such electron-scattering directions for which the orientation “independence” of the scattering intensity with respect to a specific crystallographic plane is observed and that there also exists a crystal-axis orientation for which the region of a uniform angular distribution of the intensity is observed.     

Stationary vacuum fields with a conformally flat three-space. II. Proof of axial symmetry

The conjecture is proved that stationary vacuum space-times having a conformally flat three-space are axially symmetric. The proof uses the Ernst potential and the complex conjugate potential as independent coordinates. Two field equations: a combination of the Einstein equations and an integrability condition are algebraic in one of the field variables. Their coefficients, computed by employing a REDUCE program, separately vanish unless axial symmetry holds. Solution of the coefficient equations yields the proof of axial symmetry. Certain special classes of metrics must be excluded from the discussion. The axial symmetry of these exceptional classes has been proved in I.