Related papers: Strings through the Microscope
We consider string theory in a time dependent orbifold with a null singularity. The singularity separates a contracting universe from an expanding universe, thus constituting a big crunch followed by a big bang. We quantize the theory both…
We study worldvolume actions for D-branes coupled to the worldvolume U(1) gauge field and Ramond-Ramond (RR) potentials in nonrelativistic string theory. This theory is a self-contained corner of relativistic string theory and has a string…
We describe how the D-brane spectra of the various ten-dimensional string theories can be related to general properties of the open-closed duality, encoded in the $S$ and $P$ matrices of the conformal field theory. We also complete the…
Currently, string theory represents the only advanced approach to a unification of all interactions, including gravity. In spite of the more than thirty years of its existence it did not make any empirically testable predictions. And it is…
Two different mechanisms exist in non-perturbative String / M- theory for enhanced SU(N) (SO(2N)) gauge symmetries. It can appear in type IIA string theory or M-theory near an $A_{N-1}$ (D_N) type singularity where membrnes wrapped around…
In these introductory notes I explain some basic ideas in string field theory. These include: the concept of a string field, the issue of background independence, the reason why minimal area metrics solve the problem of generating all…
The recent discovery of an explicit conformal field theory description of Type II $p$-branes makes it possible to investigate the existence of bound states of such objects. In particular, it is possible with reasonable precision to verify…
Warped supergravities with lower-dimensional branes provide consistent field-theoretic framework for discussion of important aspects of modern string theory physics. In particular, it is possible to study reliably supersymmetry breakdown…
In these notes we provide a pedagogical introduction to the subject of tachyon condensation in Witten's cubic bosonic open string field theory. We use both the low-energy Yang-Mills description and the language of string field theory to…
This talk begins with some history and basic facts about string theory and its connections with strong interactions. Comparisons of stacks of Dirichlet branes with curved backgrounds produced by them are used to motivate the AdS/CFT…
This is an introduction to the microscopic techniques of non-rational bulk and boundary conformal field theory which are needed to describe strings moving in non-compact curved backgrounds. The latter arise e.g. in the context of…
The Conformal Field Theory of the current algebra of the centrally extended 2-d Euclidean group is analyzed. Its representations can be written in terms of four free fields (without background charge) with signature ($-$+++). We construct…
We present a general analysis of the thermodynamics of spinning black p-branes of string and M-theory. This is carried out both for the asymptotically-flat and near-horizon case, with emphasis on the latter. In particular, we use the…
The dissertation consists of two parts. The first presents an account of the effective worldvolume description of $N$ coincident M2-branes ending on an M5-brane in M-theory. It reviews Basu and Harvey's recent description of the worldvolume…
We summarize recent progress in the understanding of minimal string theory, focusing on the worldsheet description of physical operators and D-branes. We review how a geometric interpretation of minimal string theory emerges naturally from…
We consider certain supersymmetric configurations of intersecting branes and branes ending on branes and analyze the duality between their open and closed string interpretation. The examples we study are chosen such that we have the lower…
String theory has been the dominating research field in theoretical physics during the last decades. Despite the considerable time elapse, no new testable predictions have been derived by string theorists and it is understandable that…
Old fashioned duality used to derive the closed string field theory for magnetic vortex from the gauge theory with Higgs scalar, is applied to the string theories. The bosonic sring theory coupled to the Kalb-Ramond 2-form field is dually…
In these lectures, I review the current status of cosmic strings and cosmic superstrings. I first discuss topological defects in the context of Grand Unified Theories, focusing in particular in cosmic strings arising as gauge theory…
This paper addresses several unsettled issues associated with string creation in systems of orthogonal Dp-D(8-p) branes. The interaction between the branes can be understood either from the closed string or open string picture. In the…