arXiv subjects

M. N. Tentyukov

Publications and source records attributed to M. N. Tentyukov.

5 recordsLinked to original sources

arXiv2008

Feynman Integral Evaluation by a Sector decomposiTion Approach (FIESTA)

Up to the moment there are two known algorithms of sector decomposition: an original private algorithm of Binoth and Heinrich and an algorithm made public lastyear by Bogner and Weinzierl. We present a new program performing the sector decomposition and integrating the expression afterwards. The program takes a set of propagators and a set of indices as input and returns the epsilon-expansion of the corresponding integral.

hep-ph↗

arXiv1998

Towards N=2 $SUSY$ Homogeneous Quantum Cosmology; Einstein--Yang--Mills systems

The application of N=2 supersymmetric quantum mechanics for the quantization of homogeneous systems coupled with gravity is discussed. Starting with the superfield formulation of an N=2 SUSY sigma model, Hermitian self-adjoint expressions for quantum Hamiltonians and Lagrangians for any signature of a sigma-model metric are obtained. This approach is then applied to coupled SU(2) Einstein-Yang-Mills (EYM) systems in axially symmetric $Bianchi$-type I, II, VIII, IX, $Kantowski-Sachs$, and closed $Friedmann-Robertson-Walker$ cosmological models. It is shown that all these models admit the embedding into the N=2 SUSY sigma model with the explicit expressions for superpotentials being direct sums of gravitational and Yang-Mills (YM) parts. In addition, the YM parts of superpotentials exactly coincide with the corresponding Chern-Simons terms. The spontaneous SUSY breaking caused by YM instantons in EYM systems is discussed in a number of examples.

gr-qc↗

arXiv1998

Evolution of Nonlinear Perturbations Inside Einstein-Yang-Mills Black Holes

We present our results on numerical study of evolution of nonlinear perturbations inside spherically symmetric black holes in the SU(2) Einstein-Yang-Mills (EYM) theory. Recent developments demonstrate a new type of the behavior of the metric for EYM black hole interiors; the generic metric exhibits an infinitely oscillating approach to the singularity, which is a spacelike but not of the mixmaster type. The evolution of various types of spherically symmetric perturbations, propagating from the internal vicinity of the external horizon towards the singularity is investigated in a self-consistent way using an adaptive numerical algorithm. The obtained results give a strong numerical evidence in favor of nonlinear stability of the generic EYM black hole interiors. Alternatively, the EYM black hole interiors of S(chwarzschild)-type, which form only a zero measure subset in the space of all internal solutions are found to be unstable and transform to the generic type as perturbations are developed.

gr-qc↗

arXiv1997

Towards Automatic Analytic Evaluation of Diagrams with Masses

A method to calculate two-loop self-energy diagrams of the Standard Model is demonstrated. A direct physical application is the calculation of the two-loop electroweak contribution to the anomalous magnetic moment of the muon ${{1/2}(g-2)}_μ$. Presently, we confine ourselves to a ``toy'' model with only $μ$, $γ$ and a heavy neutral scalar particle (Higgs). The algorithm is implemented as a FORM-based program package. For generating and automatically evaluating any number of two-loop self-energy diagrams, a special C-program has been written. This program creates the initial FORM-expression for every diagram generated by QGRAF, executes the corresponding subroutines and sums up the final results.

hep-ph↗

arXiv1995

Spherically symmetric solutions of gravitation equations on the background with spatial sections of constant curvature

We investigate the vacuum and charged spherically symmetric static solutions of the Einstein equations on cosmological background. The background metric is not flat, but curved, with constant - curvature spatial sections. Both vacuum and charged cases contain two branches. The first branches transform into the Schwarzschild and Reissner-Nordström solutions if the background metric goes to the Minkovski one. The second branches describe wormholes and have no Einstein limit.

gr-qc↗