Related papers: On the Compactification of Type IIA String Theory
We consider brane cosmologies within the context of five-dimensional actions with O(a') higher curvature corrections. The actions are compatible with bulk string amplitude calculations from heterotic string theory. We find wrapped solutions…
We consider the physical properties of four dimensional black hole solutions to the effective action describing the low energy dynamics of the gravitational sector of heterotic superstring theory. We compare the properties of the external…
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…
It is shown explicitly, that a number of solutions for the background field equations of the string effective action in space-time dimension D can be generated from any known lower dimensional solution, when background fields have only time…
We discuss a 4-dimensional nonsupersymmetric black hole solution to low energy type IIA string theory which carries D0- and D6-brane charges. For equal charges this solution reduces to the one discussed recently by Sheinblatt. We present a…
We present a class of dynamical solutions for an intersecting D4-D8 brane system in ten-dimensional type IIA supergravity. The dynamical solutions reduces to a static warped AdS_6 x S^4 geometry in a certain spacetime region. We also…
It is well-established that compactifying type I string theory on a circle \( S^{(1)} \) transforms the theory under T-duality into type I' theory, the compactification of type IIA string theory on the orbifold \(…
We show that the recent work of Lee [23] implies existence of a large class of new singularity-free strictly static Lorentzian vacuum solutions of the Einstein equations with a negative cosmological constant. This holds in all space-time…
String theory is the prime candidate for the theory of everything. However, it must be defined in ten dimensions to be consistent. To get 4D physics, the 6 other dimensions should be curled up in a small compact manifold, this procedure is…
This PhD thesis explores the properties of certain solutions in stringy effective field theories (EFTs). In the context of heterotic string theory (HST), we study $\alpha'$ corrections to well-known black hole solutions. We present…
We construct stringy cosmic string solutions corresponding to compactifications of F-theory on several elliptic Calabi-Yau manifolds by solving the equations of motion of low energy effective action of ten dimensional type IIB superstring…
We present black hole type solutions in the scalar-tensor theory with nonminimal derivative coupling to the Einstein tensor. The effects of the nonminimal derivative coupling appear in the large scales, while the solutions approach those in…
We construct supersymmetric $\mathrm{AdS}_4$ vacua of type IIB string theory in compactifications on orientifolds of Calabi-Yau threefold hypersurfaces. We first find explicit orientifolds and quantized fluxes for which the superpotential…
We propose correspondences between 4d quantum field theories with N=2,1,0 (super)conformal invariance and Type IIB string theory on various orbifolds. We argue using the spacetime string theory, and check using the beta functions (exactly…
We provide a new five dimensional black string--like solution by means of the embedding of a four dimensional regular black hole into a compact extra dimension. We enunciate a list of constraints in order to that the five dimensional black…
A discrete symmetry of the four-dimensional string effective action is employed to derive spatially homogeneous and inhomogeneous string cosmologies from vacuum solutions of general relativity that admit two commuting spacelike Killing…
We find several classes of exact classical solutions of critical bosonic string theory, constructed as twisted products of one Euclidean and one Minkowskian 2D black hole coset. One class of these solutions leads (after tensoring with free…
The cosmology of the string effective action, including one loop string threshold corrections, is analyzed for static compactifications. The stability of the minima of a general supersymmetry breaking potential is studied in the presence of…
The Cano-Ruip\'erez 4-dimensional string effective action is the simplest consistent truncation of the first-order in $\alpha'$ heterotic string effective action compactified on T$^{6}$. This theory contains, on top of the metric, a dilaton…
We present a generalization of the string's Polyakov action that describes a conformally invariant four dimensional brane. The new extended object is very different from the traditional D-branes of string theory, but, nevertheless, shares…