Related papers: Remark on the open string pair production enhancem…
We address the bosonic string pair creation in a system of parallel Dp-Dp' (p<p') branes by applying the path integral formalism. We drive the string pair creation rate by calculating the one loop vacuum amplitude of the setup in presence…
Similar to the Schwinger effect in the quantum electrodynamics, a system of two parallel D-branes at a finite separation can produce open string pairs through their interaction. In this paper, we investigate this rate for the dressed…
The rate of pair production of open strings in general uniform electromagnetic fields is calculated in various space-time dimensions. The corrections with respect to the case of pure electric backgrounds are displayed. In particular, a…
Various properties of open strings in external constant E.M. fields are reviewed. In particular, the charged-particle pair production rate in an external electric field is evaluated, and shown to reduce to Schwinger's formula in the limit…
The dynamics of a Dp brane can be described either by an open string ending on this brane or by an open D(p - 2) brane ending on the same Dp brane. The ends of the open string couple to a Dp brane worldvolume gauge field while the boundary…
All the models of elementary particles and their interactions derived from String Theory involve a compact six-dimensional internal space. Its volume and shape should be fixed or stabilized, since otherwise massless scalar fields (moduli)…
Over the last few years, string theory has changed profoundly. Most importantly, novel duality relations have emerged which involve gauge theories of brane excitations on one side and various closed string backgrounds on the other. In this…
We determine the consistent D-brane configurations in type II nonsupersymmetric Melvin Background. The D-branes are analysed from three complementary points of view: the effective Born-Infeld action, the open string partition function and…
A new configuration of non-abelian D1-branes growing into D5-branes is found. This time the effect is triggered by a non-trivial electric field on the world-volume of the D1-branes and a constant RR 4-form potential. Based on the these…
We calculate the rate of the open string pair production from the interaction of two non-intersecting D-strings at angle. The D-strings have been equipped with the $U(1)$ gauge potentials in the presence of the Kalb-Ramond field. This rate…
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…
Matrix string theory is equivalent to type IIA superstring theory in the light-cone gauge, together with extra degrees of freedom representing D-brane states. It is therefore the appropriate framework in which to study systems of multiple…
Two different mechanisms exist in non-perturbative String / M- theory for enhanced SU(N) (SO(2N)) gauge symmetries. It can appear in type IIA string theory or M-theory near an $A_{N-1}$ (D_N) type singularity where membrnes wrapped around…
Electron-positron pair production is considered for many-center systems with multiple bare nuclei immersed in a constant electric field. It is shown that there are two distinct regimes where the pair production rate is enhanced. At small…
We study the F-terms in N=1 supersymmetric, d=4 gauge theories arising from D(p+3)-branes wrapping supersymmetric p-cycles in a Calabi-Yau threefold. If p is even the spectrum and superpotential for a single brane are determined by purely…
A new mechanism for the production of electron-positron pairs from the interaction of a laser field and a fully stripped diatomic molecule in the tunneling regime is presented. When the laser field is turned off, the Dirac operator has…
We derive leading terms in the effective actions describing the coupling of bulk supergravity fields to systems of arbitrary numbers of Dp-branes and D(p+4)-branes in type IIA/IIB string theory. We use these actions to investigate the…
In this thesis we discuss some nonperturbative and noncommutative aspects of string theory. We present low-energy background field solutions corresponding to various D-branes (and their bound states) and intersecting branes in flat and…
We study the pair production of open strings in constant electric fields, using a general framework which encodes both relativistic string theory and generic linearly extended systems as well. In the relativistically invariant case we…
In this paper, which is a revised version of the author's PhD thesis, we analyze two different applications of string theory. In the first part, we focus on four dimensional compactifications of Type II string theories preserving N=1…