Introduction to Non-perturbative String Theory

In this talk I will survey some of the basic facts about superstring theories in 10 dimensions and the dualities that relate them to M theory in 11 dimensions. Then I will mention some important unresolved issues.

Lecture notes reviewing most recent developments in string/M/brane theory given by C. G. at the CIME Summer International Center of Mathematics at Cetraro. July 1997.

After briefly reviewing basic concepts of perturbative string theory, we explain in simple terms some of the new findings that created excitement among the string physicists. These developments include non-perturbative dualities and a unified picture that embraces the so-far known theories. (An overview for non-experts)

This is the written version of a set of introductory lectures on string theory.

A brief, non-technical and non-exhaustive review of D(irichlet)-branes and (some) of their applications is given.

It is an old speculation that SU(N) gauge theory can alternatively be formulated as a string theory. Recently this subject has been revived, in the wake of the discovery of D-branes. In particular, it has been argued that at least some conformally invariant cousins of the theory have such a string representation. This is a pedagogical introduction to these developments for non-string theorists. Some of the existing arguments are simplified.

This is a write-up of lectures given at the 1998 Spring School at the Abdus Salam ICTP. We give a conceptual introduction to D-geometry, the study of geometry as seen by D-branes in string theory, and to noncommutative geometry as it has appeared in D-brane and Matrix theory physics.

This talk is divided into two parts. The first part reviews some of the duality relationships between superstring theories. These relationships are interpreted as providing evidence for the existence of a unique underlying fundamental theory. The second part describes my recent work on the SL(2,Z) duality group of the type IIB superstring theory in ten dimensions and its interpretation in terms of a possible theory of supermembranes in eleven dimensions.

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 BPS vacua of supergravity is presented afterwards. As applications, we outline the role of branes in string dualities, field theory dualities, the AdS/CFT correspondence and scenarios where the string scale is at a TeV. Some issues of warp...

A brief review of some of the central ideas, terminology and techniques of the technology of orientifolds and D-branes is presented. Some applications are reviewed, including the construction of dual solitonic strings in the context of string/string duality, the computation of the Bekenstein-Hawking entropy/area law for extremal black holes, and the construction of N=1 string vacua in dimensions lower than ten. (Contribution to the proceedings of the fourth International Work...