D. V. Gal'tsov

Classical ultra-relativistic scattering in ADD

The classical differential cross-section is calculated for high-energy small-angle gravitational scattering in the factorizable model with toroidal extra dimensions. The three main features of the classical computation are: (a) It involves summation over the infinite Kaluza-Klein towers but, contrary to the Born amplitude, it is finite with no need of an ultraviolet cutoff. (b) It is shown to correspond to the non-perturbative saddle-point approximation of the eikonal amplitude, obtained by the summation of an infinite number of ladder graphs of the quantum theory. (c) In the absence of extra dimensions it reproduces all previously known results.

Filling of quasibound states by electrons in a schwarzchild field

Quasistationary states with energies Ω < Μ exist in the vicinity of a Schwarzchild black hole. The process of filling of these states by massive spinor particles is examined. The analysis is conducted in the Pauli approximation for small black holes ΜM≪ 1. In this case, it turns out that the distribution is a thermal distribution.

Exact solution of Teukolsky and Klein-Gordon radial equations in the class of type-D vacuum metrics

Exact solutions are constructed for the Teukolsky and Klein-Gordon equations for type-D asymptotically two-dimensional vacuum metrics in terms of Heuns confluent functions. The problem of coupling solutions written as a series in the vicinities of neighboring singularities is discussed. Approximate coupling equations are obtained which are valid for small values of one of the parameters of Heuns confluent function.

Synchrotron radiation in curved space—time

Synchrotron emission by ultrarelativistic particles moving in a magnetic field in curved space-time is examined by the method of local coordinates. Generally covariant equations are obtained for the radiation spectrum in the classical and quantum cases. It is shown that the relative magnitude of the quantum corrections to the radiation spectrum increases with particle motion near the event horizon in the Kerr metric. The limit of geodesic synchrotron radiation is examined.

Hidden symmetries in 5D supergravities and black rings

We construct generating technique for 5D minimal and

Form-field bremsstrahlung under collision of p-branes

U(1)^3

Physical interpretation of the Kerr-Newman-Ernst solutions

supergravities based on hidden symmetries arising in dimensional reduction to three dimensions. In the three-vector case the symmetry is SO(4,4), and the minimal case corresponds to contraction of this group to

Adiabatic expansions of green's functions in electromagnetic and gravitational fields. Radiative corrections

G_{2(2)}

Gravitational radiation of a plasma and transformation of electromagnetic waves into gravitational waves

. The matrix representation is presented applicable to both cases and the generating transformations preserving an asymptotic structure are listed. Our transformations contain enough free parameters to construct the general charged black ring in

Post-Linear Formalism for Gravitating Strings: Crossed Straight Strings Collision

U(1)^3