Related papers: Solvable N=(4,4) Type IIA String Theory in Plane-W…

This review is devoted to strings and branes. Firstly, perturbative string theory is introduced. The appearance of various types of branes is discussed. These include orbifold fixed planes, D-branes and orientifold planes. The connection to…

We propose a bottom-up approach to the building of particle physics models from string theory. Our building blocks are Type II D-branes which we combine appropriately to reproduce desirable features of a particle theory model: 1) Chirality…

We present solutions describing supersymmetric configurations of 2 or 3 orthogonally intersecting 2-branes and 5-branes of D=11 supergravity. The configurations which preserve 1/4 or 1/8 of maximal supersymmetry are 2+2, 5+5, 2+5, 2+2+2,…

We study little string theory on R^1 x S^5, defined by a theory which lives on type IIA N NS5 branes wrapped on S^5, using its supergravity dual. In particular we study semiclassical rotating closed strings in this background. We also…

Inspired by the studies of gravitational waves in anti-de Sitter universe, in general relativity, in this paper we investigate the possibility of similar solutions in IIB string theory on $AdS_3 x S^3 x R^4$. We give a general form for such…

We study D-branes in the extended geometry appearing in exceptional field theory (or exceptional generalised geometry). Starting from the exceptional sigma model (an $E_{d(d)}$ covariant worldsheet action with extra target space…

We find a large class of holographic solutions describing D4-branes wrapped on 4-manifolds $\mathcal{M}_4$ with constant curvature leading to gravity duals of supersymmetric quantum mechanics in the IR via twisted compactifications. The…

We find out a PP-wave spacetime with constant Neveu-Schwarz (NS) three form flux by taking a Penrose limit on the 1+1 dimensional intersection of two orthogonal stacks of fivebranes in type IIB string theory. We further find out an…

We discuss duality between Type IIA string theory, eleven-dimensional supergravity, and heterotic string theory in four spacetime dimensions with $N=1$ supersymmetry. We find theories whose infrared limit is trivial at enhanced symmetry…

We study the correspondence between AdS$_3$ massive IIA supergravity vacua and two-dimensional $\mathcal{N}=(0,4)$ quiver quantum field theories. After categorizing all kinds of gravity solutions, we demystify the ones that seem to reflect…

Motivated by the long-term goal of finding holographic descriptions for ${\mathcal N}=1$ and ${\mathcal N}=2$ super QCD, we revisit the subject of ''noncritical'' superstring theory. Focusing on string models with 6d super Poincar\'e…

We apply the Lie algebra expansion method to the $\mathcal{N}=1$ super-Poincar\'e algerba in four dimensions. We define a set of p-brane projectors that induce a decomposition of the super-Poincar\'e algebra preparatory for the expansion.…

We construct new M-theory solutions of M5 branes that are a realization of the fully localized ten dimensional NS5/D6 and NS5/D5 brane intersections. These solutions are obtained by embedding self-dual geometries lifted to M-theory. We…

We construct four dimensional intersecting D6-brane models that have locally the spectrum of the N=1 Supersymmetric Standard Model. All open {\em visible} string sectors share the same N=1 supersymmetry. As expected in these supersymmetric…

This thesis is based on two papers by the author and consists of two parts. We review the recent developments in the theory of multiple M2-branes and 3-algebras leading to multiple D2-brane theories. The inclusion of flux terms for the…

We present the configurations of intersecting branes in type IIA string theory corresponding to the meta-stable supersymmetry breaking vacua(hep-th/0608063) in the four-dimensional N=1 supersymmetric Yang-Mills theory coupled massive…

We analyze in the spirit of hep-th/0110039 the possible existence of supersymmetric $D p - \bar D p$ brane systems in flat ten dimensional Minkowski space. For $p=3,4$ we show that besides the solutions related by T-duality to the $D2 -…

$D$-brane boundary states for type II superstrings are constructed by enforcing the conditions that preserve half of the space-time supersymmetry. A light-cone coordinate frame is used where time is identified as one of the coordinates…

We discuss non-linear instantons in supersymmetric field theories on curved spaces arising from D-branes. Focusing on D3-branes and four-dimensional field theories, we derive the supersymmetry conditions and show the intimate relation…

Dualities between certain supersymmetric gauge field theories in three and four dimensions have been studied in considerable detail recently, by realizing them as geometric manipulations of configurations of extended objects in type II…