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O. V. Kechkin

Publications and source records attributed to O. V. Kechkin.

7 recordsLinked to original sources
arXiv2017

Least action principle for Lorentz force in dilaton-Maxwell electrodynamics

The least action principle is established for the dynamics of a test particle in a dilaton-Maxwell background. These dynamics and background are invariant under the action of the dilatation transformation; explicit form of the corresponding generalization of the Lorentz force is established for the considered model. On a stationary background, we have found the integral of motion of the energy type. This integral is used to resolve the radial dynamics of test particles in a spherically symmetric electrostatic background.

physics.gen-ph↗
arXiv1996

Hidden Symmerties in Dilaton--Axion Gravity

Four--dimensional Einstein--Maxwell--dilaton--axion system restricted to space--times with one non--null Killing symmetry is formulated as the three--dimensional gravity coupled sigma--model. Several alternative representations are discussed and the associated hidden symmetries are revealed. The action of target space isometries on the initial set of (non--dualized ) variables is found. New mulicenter solutions are obtained via generating technique based on the formulation in terms of the non--dualized variables.

gr-qc↗
arXiv1995

Matrix Dilaton-Axion for Heterotic String in Three Dimensions

New and surprisingly simple representation is found for the heterotic string bosonic effective action in three dimensions in terms of complex potentials. The system is presented as a Kähler $σ$--model using complex symmetric $2\times 2$ matrix (matrix dilaton--axion) which depends linearly on three Ernst--type potentials and transforms under $U$--duality via matrix valued $SL(2,R)$. Two discrete automorphisms relating ten isometries of the target space (U--duality transformations) are found and used to generate the non--trivial Ehlers--Harrison sector by a map from the trivial gauge sector. Finite transformations are obtained in a simple form in terms of complex potentials. New solution generating technique is used to construct EMDA double--Kerr solution.

hep-th↗
arXiv1995

U-Duality and Symplectic Formulation of Dilaton-Axion Gravity

We study a bosonic four--dimensional effective action corresponding to the heterotic string compactified on a 6--torus (dilaton--axion gravity with one vector field) on a curved space--time manifold possessing a time--like Killing vector field. Previously an existence of the $SO(2,3)\sim Sp(4, R)$ global symmetry ($U$--duality) as well as the symmetric space property of the corresponding $σ$--model have been established following Neugebauer and Kramer approach. Here we present an explicit form of the $Sp(4, R)$ generators in terms of coset variables and construct a representation of the coset in terms of the physical target space coordinates. Complex symmetric $2\times 2$ matrix $Z$ (``matrix dilaton --axion'') is introduced for which $U$--duality takes the matrix valued $SL(2, R)$ form. In terms of this matrix the theory is further presented as a Kähler $σ$--model. This leads to a more concise $2\times 2$ formulation which opens new ways to construct exact classical solutions. New solution (corresponding to constant ${\rm Im} Z$ ) is obtained which describes the system of point massless magnetic monopoles endowed with axion charges equal to minus monopole charges. In such a system mutual magnetic repulsion is exactly balanced by axion attraction so that the resulting space time is locally flat but possesses multiple Taub--NUT singularities.

hep-th↗
arXiv1995

Symmetries of the stationary Einstein--Maxwell--dilaton theory

Gravity coupled three--dimensional $σ$--model describing the stationary Einstein--Maxwell--dilaton system with general dilaton coupling is studied. Killing equations for the corresponding five--dimensional target space are integrated. It is shown that for general coupling constant $α$ the symmetry algebra is isomorphic to the maximal solvable subalgebra of $sl(3,R)$. For two critical values $α=0$ and $α=\sqrt{3}$, Killing algebra enlarges to the full $sl(3,R)$ and $su(2,1)\times R$ algebras respectively, which correspond to five--dimensional Kaluza--Klein and four--dimensional Brans--Dicke--Maxwell theories. These two models are analyzed in terms of the unique real variables. Relation to the description in terms of complex Ernst potentials is discussed. Non--trivial discrete maps between different subspaces of the target space are found and used to generate new arbitrary--$α$ solutions to dilaton gravity.

hep-th↗
arXiv1994

Ehlers--Harrison--Type Transformations in Dilaton--Axion Gravity

The ten--parametric internal symmetry group is found in the $D=4$ Einstein--Maxwell--Dilaton--Axion theory restricted to space--times admitting a Killing vector field. The group includes dilaton--axion $SL(2,R)$ duality and Harrison--type transformations which are similar to some target--space duality boosts, but act on a different set of variables. New symmetry is used to derive a seven--parametric family of rotating dilaton--axion Taub--NUT dyons.

hep-th↗