Related papers: Cosmic D- and DF-strings from D3Dbar3: Black Strin…
Very much as extremal Reissner-Nordst\"om BHs, D3-branes and their intersecting bound-states in lower dimensions enjoy a remarkable symmetry under conformal inversions that exchange the horizon with infinity and keep the photon-sphere…
An exact solution, in which a D2-brane and an anti-D2-brane are connected by an elliptically tubular D2-brane, is obtained without any junction condition. The solution is shown to preserve one quarter of the supersymmetries of the type-IIA…
We examine the system where a string stretches between pair of D-branes, and study the bending of the D-brane caused by the tension of the string. If the distance between the pair of D-branes is sent to infinity, the tension of the string…
We derive the BPS mass formulae of the Dirichlet branes from the Born-Infeld type action. BPS saturation is realized when the brane has the minimal volume while keeping the appropriate winding numbers. We apply the idea to two cases, type…
We study some aspects of Maldacena's large $N$ correspondence between N=4 superconformal gauge theory on D3-brane and maximal supergravity on AdS_5xS_5 by introducing macroscopic strings as heavy (anti)-quark probes. The macroscopic strings…
We present a simple example of a supersymmetric attractor mechanism in the purely open string context of D-branes embedded in curved space-time. Our example involves a class of D3-branes embedded in the 2-charge D1-D5 background of type IIB…
The existence of cusps on non-periodic strings ending on D-branes is demonstrated and the conditions, for which such cusps are generic, are derived. The dynamics of F-, D-string and FD-string junctions are investigated. It is shown that…
We point out that in the limit of large number of dimensions a wide class of non-extremal neutral black holes has a universal near horizon limit. The limiting geometry is the two-dimensional black hole of string theory with a…
We solve the dilaton field equation in the background of a spherically symmetric black hole in bosonic or heterotic string theory with curvature-squared corrections in arbitrary d spacetime dimensions. We then apply this result to obtain a…
We show the existence of classical solutions of a system of D3-branes oriented at an arbitrary angle with respect to each other, in a six dimensional pp-wave background obtained from AdS_3\times S^3\times R^4, with NS-NS and R-R 3-form…
We consider non-spherically symmetric perturbations of the uncharged black string/flat black brane in the large dimension (D) limit of general relativity. We express the perturbations in a simplified form using variables introduced by…
The quantum corrections to the counting of statistical entropy for the 5+1-dimensional extremal black string in type-IIB supergravity with two observers are studied using anomalous Wess-Zumino actions for the corresponding intersecting…
The tachyon effective field theory describing the dynamics of a non-BPS D-$p$-brane has electric flux tube solutions where the electric field is at its critical value and the tachyon is at its vacuum. It has been suggested that these…
In the thesis we analize different problems related to the supersymmetric extension of the Dirac-Born-Infeld action. In chapter 2 we introduce the DBI action and show how it appears in string theory, we discuss also it's connection with…
The periodic bounce of Born-Infeld theory of $D3$-branes is derived, and the BPS limit of infinite period is discussed as an example of tachyon condensation. The explicit bounce solution to the Born--Infeld action is interpreted as an…
We investigate how the presence of RR magnetic $F_{p+2}$ fluxes affects the energy of classical Dp branes, for specific string theory supersymmetric backgrounds which are solutions to the leading order in $\alpha'$ including back-reaction…
Supersymmetry of five dimensional string solutions is examined in the context of gauged D=5, N=2 supergravity coupled to abelian vector multiplets. We find magnetic black strings preserving one quarter of supersymmetry and approaching the…
We investigate BPS properties of the charged soliton solutions of D-brane worldvolume theory, which is described by the supersymmetric Dirac-Born-Infeld action, by means of the N=2 target-space supersymmetry algebra. Our results agree with…
We study the properties of a D-brane in the presence of $k$ NS5 branes. The Dirac-Born-Infeld action describing the dynamics of this D-brane is very similar to that of a non-BPS D-brane in ten dimensions. As the D-brane approaches the…
In the present work, the gravitational field of superconducting cosmic string has been investigated in the context of Brans-Dicke theory of gravity. We have presented two kind of solutions for the spacetime in the far field zone of the…