Related papers: A Comment on Zero-brane Quantum Mechanics

We suggest that some of the remarkable results on stringy dynamics which have been found recently indicate the existence of another dynamical length scale in string theory that, at weak coupling, is much shorter than the string scale. This…

We show that the solution of a pre-geometric strongly coupled quantum mechanical model describing K D-particles in the presence of N D4-branes in type IIA string theory, at fixed K and large N, yields an effective action describing the…

The null-brane background is a simple smooth 1/2 BPS solution of string theory. By tuning a parameter, this background develops a big crunch/big bang type singularity. We construct the DLCQ description of this space-time in terms of a…

We study D-branes of N=2 supersymmetric sigma models. Supersymmetric nonlinear sigma models with 2-dimensional target space have D0,D1,D2-branes, which are realized as A-,B-type supersymmetric boundary conditions on the worldsheet. When we…

I argue that the linearity of quantum mechanics is an emergent feature at the Planck scale, along with the manifold structure of space-time. In this regime the usual causality violation objections to nonlinearity do not apply, and nonlinear…

In a previous study we showed that D0-branes (particles) can operate as sources of very-high-energy radiation, as a result of an unstable spacetime distortion that follows a D0-particle/closed string state scattering. The effect can happen…

We discuss the possibility of quintessence in the dilatonic domain walls including the Randall-Sundrum brane world. We obtain the zero mode effective action for gravitating objects in the dilatonic domain wall. First we consider the four…

D-branes are string theory solitons defined by boundary conditions on open strings that end on them. They play an important role in the non-perturbative dynamics of string theory and have found a wide range of applications. These lectures…

We study vortex-strings in four-dimensional N=2 supersymmetric SU(Nc)xU(1) gauge theories with Nf hypermultiplets in the fundamental representation of SU(Nc) and general U(1) charges. If Nf>Nc, the vacuum is not gapped and the low-energy…

We study brane cosmology as 4D (4-dimensional) domain wall dynamics in 5D bulk spacetime. For a generic 5D bulk with 3D maximal symmetry, we derive the equation of motion of a domain wall and find that it depends on mass function of the…

String theory proves to be an imperative tool to explore the critical behavior of the quantum dissipative system. We discuss the quantum particles moving in two dimensions, in the presence of a uniform magnetic field, subject to a periodic…

String-brane interactions provide an ideal framework to study the dynamics of the massive states of the string spectrum in a non-trivial background. We present here an analysis of tree-level amplitudes for processes in which an NS-NS string…

On an unstable D-brane, the rolling of the tachyon away from the maximum of its potential is described by time-dependent solutions in string theory. Subsequent analysis leads to an understanding of physics around the tachyon vacuum in terms…

We investigate a D-brane system in which spontaneous gauge symmetry breaking occurs. The system consists of four D3-branes and three anti-D7-branes at C^3/Z_3 singularity. The singularity is blown up by vacuum expectation values of the…

We review a number of perturbative calculations describing the interactions of D-branes with massless elementary string states. The form factors for the scattering of closed strings off D-branes are closely related to the Veneziano…

We systematically investigate open strings in the plane wave background of type IIB string theory. We carefully analyze possible boundary conditions for open strings and find static as well as time-dependent branes. The branes fall into…

D-brane technology and strong/weak coupling duality supplement traditional orbifold techniques by making certain background geometries more accessible. In this spirit, we consider some of the geometric properties of the type IIB theory on…

We study the boundary state associated with the decay of an unstable D-brane with uniform electric field, 1>e>0 in the string units. Compactifying the D-brane along the direction of the electric field, we find that the decay process is…

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…

We study the properties of the topologically nontrivial doublet solution arisen in the biscalar theory with a fourth-power potential introducing an example of the spontaneous breaking of symmetry. We rule out the zero-brane (non-minimal…