Related papers: Fundamental strings and NS5-branes from unstable D…
We present an analytic solution for tachyon condensation on a non-BPS D-brane in Berkovits' open superstring field theory. The solution is presented as a product of $2\times 2$ matrices in two distinct $GL_2$ subgroups of the open string…
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…
We examine the fluctuations around a Dp-brane solution in an unstable D-brane system using boundary states and also boundary string field theory. We show that the fluctuations correctly reproduce the fields on the Dp-brane. Plugging these…
The stringy description for the instabilities in the $RR$ charged $D_{p}-\bar{D}_{p}$ pairs is now well understood in terms of the open string tachyon condensation. The quantum interpretation presumably via the stringy description for the…
We study the tachyon condensation of the D-\bar{D}-brane system with a constant tachyon vev in the context of classical solutions of the Type II supergravity. We find that the general solution with the symmetry ISO(1,p)xSO(9-p) (the…
We consider the type 0 theories, obtained from the closed NSR string by a diagonal GSO projection which excludes space-time fermions, and study the D-branes into these theories. The low-energy dynamics of N coincident D-branes is governed…
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…
In a tachyon model proposed by Minahan and Zwiebach and derived in the boundary string field theory, we construct various new solutions which correspond to nontrivial brane configurations in string theory. Our solutions include Dp-D(p-2)…
Unstable, non-BPS D-branes in weakly coupled ten dimensional string theory have many mysterious properties. Among other things, it is not clear what sets their tension, what is their relation to the better understood BPS D-branes, and why…
We present our searches for the tubular bound states of a D2-brane with $m$ D0-branes and $n$ fundamental strings in the NS5-brane, Dp-brane or macroscopic strings background by solving the Dirac-Born-Infeld equation. The geometry of…
We study noncommutative (NC) field theory of a real NC tachyon and NC U(1) gauge field, describing the dynamics of an unstable D$p$-brane. For every given set of diagonal component of open string metric $G_{0}$, NC parameter $\theta_{0}$,…
Metastable supersymmetry breaking configurations of D-branes and NS5-branes in string theory often owe their existence to classical gravitational interactions between the branes. We show that in the effective theory of the light fields,…
We show how a solitonic ``magnetically'' charged $p$-brane solution of a given supergravity theory, with the magnetic charge carried by an antisymmetric tensor gauge field, can be generalized to a dyonic solution. We discuss the cases of…
We consider non-supersymmetric $p$-brane solutions of type II string theories characterized by three parameters. When the charge parameter vanishes and one of the other two takes a specific value, the corresponding chargeless solutions can…
We review how to describe the stable non-BPS D-branes of type II string theory from a classical perspective, and discuss the properties of the space-time geometry associated to these configurations. This is relevant in order to see whether…
This paper is devoted to the construction of unstable D-brane action in torsional Newton-Cartan background through T-duality along null direction. We determine corresponding equations of motion and analyze their solution that corresponds to…
The properties of brane-antibrane systems and systems of unstable D-branes in Type II superstring theory are investigated using the formalism of superconnections. The low-energy open string dynamics is shown to be probed by generalized…
Modifications to the singularity structure of D3-branes that result from turning on a flux for the R-R and NS-NS 3-forms (fractional D3-branes) provide important gravity duals of four-dimensional N=1 super-Yang-Mills theories. We construct…
We consider closed string tachyons localized at the fixed points of noncompact nonsupersymmetric orbifolds. We argue that tachyon condensation drives these orbifolds to flat space or supersymmetric ALE spaces. The decay proceeds via an…