No abstract

The ten-parametric internal symmetry group is found in the D = 4 EinsteinMaxwell-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. PASC number(s): 97.60.Lf, 04.60.+n, 11.17.+y 1

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 = √ 3, Killing algebra enlarges to the full sl(3, R) and su(2, 1)×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.

Using the Ernst potential formulation we construct all the finite symmetry transformations which preserve the asymptotics of the bosonic fields of the (dϩ3)-dimensional low-energy heterotic string theory compactified on a d-torus. We combine all the dynamical variables into a single (dϩ1)ϫ(dϩ1ϩn)-dimensional matrix potential which linearly transforms under the action of these symmetry transformations in a transparent SO(2,dϪ1)ϫSO(2,dϪ1ϩn) way, where n is the number of Abelian vector fields. We formulate the most general solution generation technique based on the use of these symmetries and show that they form the invariance group of the general Israel-Wilson-Perjés class of solutions.