This review is devoted to open strings, and in particular to the often surprising features of
their spectra. It follows and summarizes developments that took place mainly at the …

The physical motivations and the basic construction rules for type I strings and M-theory
compactifications are reviewed in the light of recent developments. The first part of this …

We formulate rational conformal field theory in terms of a symmetric special Frobenius
algebra A and its representations. A is an algebra in the modular tensor category of Moore …

In this note we explain how world-volume geometries of D-branes can be reconstructed
within the microscopic framework where D-branes are described through boundary …

We show how to construct chiral tachyon-free perturbative orientifold models, where
supersymmetry is broken at the string scale on a collection of branes while, to lowest order …

In the presence of internal magnetic fields, a D9 brane can acquire a D5 (or anti-D5) RR
charge, and can therefore contribute to the corresponding tadpole. In the resulting vacua …

We develop further the theory of Rational Conformal Field Theories (RCFTs) on a cylinder
with specified boundary conditions emphasizing the role of a triplet of algebras: the Verlinde …

A bstract The study of conformal boundary conditions for two-dimensional conformal field
theories (CFTs) has a long history, ranging from the description of impurities in one …

We show how chiral type I models whose tadpole conditions have no supersymmetric
solution can be consistently defined introducing antibranes with non-supersymmetric world …

We explain how D-branes on group manifolds are stabilized against shrinking by quantized
worldvolume U (1) fluxes. Starting from the Born-Infeld action in the case of the SU (2) group …