Related papers: Geometry from Matrices via D-branes
We study the classical geometry produced by a stack of stable (i.e. tachyon free) non-BPS D-branes present in K3 compactifications of type II string theory. This classical representation is derived by solving the equations of motion…
We lay down an elementary yet fundamental lemma concerning a finite algebraicness property of a smooth map from an Azumaya/matrix manifold with a fundamental module to a smooth manifold. This gives us a starting point to build a synthetic…
A system of k Neveu-Schwarz (NS) 5-branes of type II string theory with one transverse direction compactified on a circle admits various unstable D-brane systems, - some with geometric instability arising out of being placed at a point of…
We discuss the nonabelian world-volume action which governs the dynamics of N coincident Dp-branes. In this theory, the branes' transverse displacements are described by matrix-valued scalar fields, and so this is a natural physical…
Using the construction of D-branes with nonzero $B$ field in the matrix model we give a physical interpretation of the known background independence in gauge theories on a noncommutative space. The background independent variables are…
We investigate the spatially inhomogeneous decay of an unstable D-brane and construct an asymptotic solution which describes a codimension one D-brane and the tachyon matter in boundary string field theory. In this solution, the tachyon…
We study tachyon condensation on noncommutative toric orbifolds with a $Z_2$ discrete group and explore the various kins of brane bound states arising in the case of irrational values of the B-field. We show that $Z_$ symmetry of the…
We discuss a matrix model for D0-branes on S^3 \times M^7 based on quantum group symmetries. For finite radius of S^3 (i.e. for finite k), it gives results beyond the reach of the ordinary matrix model. For large k all known static…
The mechanism of recombination of intersecting D-branes is investigated within the framework of effective tachyon field theory. We regard the branes as the kink-type tachyon condensed states and use the effective two-tachyon Lagrangian to…
We construct boundary states for D-branes which carry traveling waves in the covariant formalism. We compute their vacuum amplitudes to investigate their interactions. In non-compact space, the vacuum amplitudes become trivial as is common…
In this paper, we study a new matrix theory based on non-BPS D-instantons in type IIA string theory and D-instanton - anti D-instanton system in type IIB string theory, which we call K-matrix theory. The theory correctly incorporates the…
We introduce generalized calibrations that take into account the gauge field on the D-brane so that calibrated submanifolds minimize the Dirac-Born-Infeld energy. We establish the calibration bound and show that the calibration form is…
The description of D-branes as boundary states for type II string theories (in the covariant formulation) requires particular care in the R-R sector. Also the vertices for R-R potentials that can couple to D-branes need a careful handling.…
The interaction between the intersecting noncommutative D-branes (or membranes) is investigated within the M(atrix) theory. We first evaluate the spectrum of the off-diagonal fluctuation and see that there is a tachyon mode, which signals…
In this paper we construct path integral representations of the boundary states in some special backgrounds such as the U(1) gauge field background, the linear dilaton background and the open string tachyon background. The initial purpose…
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)…
We discuss the tachyon condensation in a single unstable D-brane in the framework of boundary state formulation. The boundary state in the background of the tachyon condensation and the NS B-field is explicitly constructed. We show in both…
This is a write-up of lectures given at the 1998 Spring School at the Abdus Salam ICTP. We give a conceptual introduction to D-geometry, the study of geometry as seen by D-branes in string theory, and to noncommutative geometry as it has…
We compute the boundary state associated with a moving D$p$-brane in the presence of the open string tachyon field as a background field. The effect of the tachyon condensation on the boundary state will be discussed. It leads to a boundary…
We summarize how to describe D-branes in a matrix theory based on unstable D-instantons, which we call K-matrix theory, and explicity show that D-branes can be constructed as bound states of infinitly many unstable D-instantons. We examine…