Related papers: String Effective Action and Two Dimensional Charge…
It is observed that the three-dimensional BTZ black hole is a supersymmetric solution of the low-energy field equations of heterotic string theory compactified on an Einstein space. The solution involves a non-zero dilaton and NS-NS…
We consider three-dimensional gravity with negative cosmological constant in the presence of a scalar and an Abelian gauge field. Both fields are conformally coupled to gravity, the scalar field through a nonminimal coupling with the…
We study aspects of d-dimensional black holes with two electric charges, corresponding to fundamental strings with generic momentum and winding on an internal circle. The perturbative alpha' corrections to such black holes and their…
We study $D$-dimensional charged static spherically symmetric black hole solutions in Gauss-Bonnet theory coupled to nonlinear electrodynamics defined as arbitrary functions of the field invariant and constrained by several physical…
Four dimensional heterotic string effective action is known to admit non-rotating electrically and magnetically charged black hole solutions. It is shown that the partition functions and entropies in both the cases are identical when these…
We determine the $s$-waves contribution of a scalar field to the four dimensional effective action for arbitrary spherically symmetric external gravitational fields. The result is applied to $4d$-black holes and it is shown that the energy…
We construct dynamical many-black-hole spacetimes with well-controlled asymptotic behavior as solutions of the Einstein vacuum equation with positive cosmological constant. We accomplish this by gluing Schwarzschild-de Sitter or Kerr-de…
In this paper, we present static and spherically symmetric vacuum solutions to the mass-dimension $d\leq 4$ action of an effective-field theory, choosing the diffeomorphism symmetry to be broken explicitly. By using the reduced-action…
Using a solution generating technique based on the symmetries of the dimensionally reduced Lagrangian we derive two exact solutions of the Einstein-Maxwell-Dilaton field equations in five dimensions. More specifically, these solutions…
We generate from the static charged BTZ black hole a family of spinning charged solutions to the Einstein-Maxwell equations in 2+1 dimensions. These solutions go over, in a suitable limit, to self-dual spinning charged solutions, which are…
We study solutions of the tree level string effective action in the presence of the tachyon mode.We find that the 2-dim. static black hole is stable against tachyonic perturbations.For a particular ansatz for the tachyon field we find an…
We study the cosmological solutions of the one loop corrected superstring effective action, in a Friedmann-Robertson-Walker background, and in the presence of the dilaton and modulus fields. A particularly interesting class of solutions is…
A two-dimensional (2D) dilaton gravity model, whose static solutions have the same features of the Reissner-Nordstrom solutions, is obtained from the dimensional reduction of a four-dimensional (4D) string effective action invariant under…
We consider a class of Einstein-Maxwell-dilaton theories in general dimensions and construct both static and dynamic charged black holes. We adopt the reverse engineering procedure and make a specific ansatz for the scalar field and then…
We present time-dependent analytic solutions to the Einstein equations coupled with a dilaton (scalar) field. The background geometry for the solutions is a product of an N-dimensional spherically symmetric space and a d-dimensional flat…
It is shown that the five-dimensional anti-de Sitter black hole is a supersymmetric solution of the low-energy field equations of type IIB string theory compactified on an Einstein space. A statistical interpretation of the mass dependence…
An exact solution of Einstein - Maxwell - conformal scalar field equations is given, which is a black hole solution and has three parameters: scalar charge, electric charge, and magnetic charge. Switching off the magnetic charge parameter…
We study black hole solutions in the Einstein gravity with Gauss-Bonnet term, the dilaton and a positive "cosmological constant" in various dimensions. Physically meaningful black holes with a positive cosmological term are obtained only…
We examine the axi-dilatonic sector of low energy string theory and demonstrate how the gravitational interactions involving the axion and dilaton fields may be derived from a geometrical action principle involving the curvature scalar…
The generalization of the black hole in three-dimensional spacetime to include an electric charge Q in addition to the mass M and the angular momentum J is given. The field equations are first solved explicitly when Q is small and the…