Related papers: Closed Strings as Imaginary D-branes

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…

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 use the boundary state formalism to study, from the closed string point of view, superpositions of branes and anti-branes which are relevant in some non-perturbative string dualities. Treating the tachyon instability of these systems as…

We use the boundary state formalism for the bosonic string to calculate the emission amplitude for closed string states from particular D-branes. We show that the amplitudes obtained are exactly the same as those obtained from the…

It has been known for about thirty years that a scattering amplitude involving D0-branes and closed strings suffers from infrared divergences beyond tree level. These divergences arise because the conventional world-sheet approach cannot…

We consider SO(4) x SO(6) invariant type IIB string solution describing D3-branes superposed with D-instantons homogeneously distributed over D3-brane world-volume. In the near D3-brane horizon limit this background interpolates between…

I discuss a model inspired from the string/brane framework, in which our Universe is represented as a three brane, propagating in a bulk space time punctured by D0-brane (D-particle) defects. As the D3-brane world moves in the bulk, the…

We perform the consistent quantization of open string D-brane in non-constant NS-NS closed string B field background by directly imposing the worldsheet conformal symmetry. In addition to the previous noncommutative D-brane coordinates…

D-branes intersecting at an arbitrary fixed angle generically constitute a configuration unstable toward recombination. The reconnection of the branes nucleates at the intersection point and involves a generalization of the process of brane…

We realize the CFT with target a lens space SU(2)/Z_l as a simple current construction. This allows us to compute the boundary states and the annuli coefficients, and in particular to study the B-type branes, in purely algebraic terms.…

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…

Starting from the boundary CFT definition for the D-branes in vacuum string field theory (VSFT) given in hep-th/0105168, we derive the oscillator expression for the D24-brane solution in the VSFT on D25-brane. We show that the state takes…

We show that the boundary string field theory (BSFT) on unstable D0-branes in 2d string theory is equivalent to the double scaled c=1 matrix model (i.e. quadratic action), even though we naively expect many interaction terms in BSFT. It is…

We define a sequence of VSFT D-branes whose low energy limit leads exactly to a corresponding sequence of GMS solitons. The D-branes are defined by acting on a fixed VSFT lump with operators defined by means of Laguerre polynomials whose…

We study open strings in the noncritical $c=1$ bosonic string theory compactified on a circle at self-dual radius. These strings live on D-branes that are extended along the Liouville direction ({\it FZZT} branes). We present explicit…

Building on earlier work, we construct linear sigma models for strings on curved spaces in the presence of branes. Our models include an extremely general class of brane-worldvolume gauge field configurations. We explain in an accessible…

It is shown how some field theories in the target-space induce the splitting of the space-time into a continuous of branes, which can be p-branes or D-branes depending on what the field theory it is. The basic symmetry underlying the…

We study D-branes that preserve a diagonal SL(2) affine Lie algebra in string theory on AdS_3. We find three classes of solutions, corresponding to the following representations of SL(2): (1) degenerate, finite dimensional representations…

We consider Dirichlet p-branes in type II string theory on a space which has been toroidally compactified in d dimensions. We give an explicit construction of the field theory description of this system by putting a countably infinite…

We construct supersymmetric brane solutions in string and M-theory with moduli parameters that depend arbitrarily on the light-cone time. Our investigation aims in understanding time dependent phenomena in gauge theories at strong coupling…