Related papers: p-p' System with B Field and Projection Operator N…
In this PhD thesis the low energy effective actions for D-branes and the M5-brane are used to analyze the dynamics of brane probes moving in the geometry created by diverse supergravity backgrounds. It begins with an introduction to string…
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…
At first, we derive a boundary state, associated with a moving D$p$-brane, in the presence of the Kalb-Ramond field and a $U(1)$ gauge potential. Then, from the interaction of such D$p$-branes, we obtain the radiation amplitude for a…
The open string ending on a D-brane with a constant B-field in a pp-wave Ramond-Ramond background is exactly solvable. The theory is controlled by three dimensionful parameters: alpha', the mass parameter (RR background times the lightcone…
We use the `branes within branes' approach to study the appearance of stable $ (p-2)-branes and unstable (p-1)-branes in type II string theory from p-brane--p-antibrane pairs.Our goal is to describe the emergence of these lower dimensional…
When unstable Dp-branes in type II string theory are placed in a B-field, the resulting tachyonic world-volume theory becomes noncommutative. We argue that for large noncommutativity parameter, condensation of the tachyon as a…
Method for computing scattering amplitudes of open strings with Dirichlet boundary on one end and Neumann boundary condition on the other is described. Vertex operator for these states are constructed using twist fields which have been…
We discuss a new class of brane models (extending both p-brane and Dp-brane cases) where the brane tension appears as an additional dynamical degree of freedom instead of being put in by hand as an ad hoc dimensionfull scale. Consistency of…
We apply the boundary state method and operator formalism to obtain tree-level scattering amplitude of the Kalb-Ramond state from a D$p$-brane. The brane has a tangential dynamics, and it has been dressed by the antisymmetric tensor field,…
Continuing the study in hep-th/0004092 and hep-th/0004092, we investigate a non-trivial string dynamical process related to orientifold planes, i.e., the splitting of physical NS-branes and D(p+2)-branes on orientifold Op-planes. Creation…
We calculate the potential for $Dp-\Dbar p$ pair and show that the coincident $Dp-\Dbar p$ system has $(11-p)$ tachyonic modes, with $(9-p)$ of them due to radiative corrections. We propose that the decay width of an unstable…
We review two types of D-branes processes where open strings are created. In the first type, a closed string incident on a collection of D-branes is converted into a number of open strings running along them. For the case of threebranes we…
In this paper, we consider the D-brane, especially ${\rm D}_-$-brane, in the pp-wave background, which has the eight dynamical and the eight kinematical supercharges. Since the pp-wave background has not a SO(8) but a ${\rm SO}(4) \times…
We address the bosonic string pair creation in a system of parallel Dp-Dp' (p<p') branes by applying the path integral formalism. We drive the string pair creation rate by calculating the one loop vacuum amplitude of the setup in presence…
By evaluating string scattering amplitudes, we investigate various low energy interactions for the massless scalars on a nonabelian Dirichlet brane. We confirm the existence of couplings of closed string fields to the world-volume scalars,…
We investigate the criterion, on the Born-Infeld background fields, for the open string pair creation to occur in D$p$-(anti-)D$p$-brane systems. Although the pair creation occurs generically in both D$p$-D$p$ and D$p$-anti-D$p$ systems for…
We derive fully covariant expressions for all two-point scattering amplitudes of two massless closed strings from a Dirichlet $p$-brane. This construction relies on the observation that there is a simple relation between these D-brane…
We study the physics of D-branes in the presence of constant Ramond-Ramond potentials. In the string field theory context, we first develop a general formalism to analyze open strings in gauge trivial closed string backgrounds, and then…
We study the motion of a D(8-p)-brane probe in the background created by a stack of non-threshold (D(p-2), Dp) bound states for $2\le p\le 6$. The brane probe and the branes of the background have two common directions. We show that for a…
In the context of the superstring theory, we calculate the radiation amplitude of a general massless closed string from the interaction of two parallel D$p$-branes. The background field is the constant antisymmetric tensor $B_{\mu\nu}$, and…