相关论文: D branes in string theory, II

The Dirac-Born-Infeld action with transverse scalar fields is considered to study the dynamics of various BPS states. We first describe the characteristic properties of the so-called 1/2 and 1/4 BPS states on the D3 brane, which can be…

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 review the boundary state description of D-branes in type I string theory and show that the only stable non-BPS configurations are the D-particle and the D-instanton. We also compute the gauge and gravitational interactions of the…

We present a pedagogical review of the stable non-BPS states in string theory which have recently attracted some attention in the literature. In particular, following the analysis of A. Sen, we discuss in detail the case of the stable…

In these lectures we present a detailed description of the origin and of the construction of the boundary state that is now widely used for studying the properties of D branes. (Lectures given at NATO-ASI on "Quantum Geometry" in Akureyri,…

We determine the boundary state for both the NS-NS and R-R sectors of superstring theory. We show how they are modified under a boost. The boosted boundary state is then used for computing the interaction of two D-branes moving with…

In this Ph.D. thesis, we study some aspects of strings and branes. We mainly focus on anomalous D-brane couplings and on non-supersymmetric branes. In Chapter 2, we illustrate three key concepts in a field theory context: duality,…

We discuss D-branes from a conformal field theory point of view. In this approach, branes are described by boundary states providing sources for closed string modes, independently of classical notions. The boundary states must satisfy…

In this article, applying different types of boundary conditions; Dirichlet, Neumann, or Mixed, on open strings we realize various new brane bound states in string theory. Calculating their interactions with other D-branes, we find their…

We study semi-classical rotating open strings ending on a probe Dp-brane close to a stack of extremal, non-extremal Dp-branes and Dp-branes with $B$-fields. These states may be interpreted as positronium-like bound states of spinning…

We review the recent developments in our understanding of non-BPS states and branes in string theory. The topics include 1) construction of unstable non-BPS D-branes in type IIA and type IIB string theories, 2) construction of stable…

We construct a system of bosonic closed string field theory coupled to a D-brane. The interaction between the D-brane and closed string field is introduced using the boundary state which is a function of constant field strength $F_{\mu\nu}$…

In these lectures we start with a pedagogical introduction of the properties of open and closed superstrings and then, using the open/closed string duality, we construct the boundary state that provides the description of the maximally…

There are two families of non-BPS bi-spinors in the perturbative spectrum of the nine dimensional heterotic string charged under the gauge group $SO(16)\times SO(16)$. The relation between these perturbative non-BPS states and certain…

In this thesis I present applications of the Born-Infeld action to the description of D-branes, mostly in the context of type IIB string theory. First I present the Callan-Maldacena construction of a fundamental string attached to a…

A review of various aspects of superstrings in background electromagnetic fields is presented. Topics covered include the Born-Infeld action, spectrum of open strings in background gauge fields, the Schwinger mechanism, finite-temperature…

Using the boundary string field theory (BSFT) techniques we study the boundary state and partition function for a dynamical (rotating-moving) D$p$-brane coupled to the electromagnetic and tachyonic background fields in superstring theory.…

In these lectures we review the basic ideas of perturbative and non-perturbative string theory. On the non-perturbative side we give an introduction to D-branes and string duality. The elementary concepts of non-BPS branes and…

All bound states of fundamental strings, D-branes and NS-branes of string theory, both type-IIA and type-IIB, which may be described by a null geodesic motion on the coset G/K(G) where G is a group of type A, D or E embedded within E(11)…

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…