Some Properties of Type I' String Theory

The T-dual formulation of Type I superstring theory, sometimes called Type I' theory, has a number of interesting features. Here we review some of them including the role of D0-branes and D8-branes in controlling possible gauge symmetry enhancement.Comment: 10 pages; Submitted to a volume in memory of Yuri Golfand; v2: reference adde

Some Recent Progress in AdS/CFT

Much of modern string theory research concerns AdS/CFT duality, or more generally, gauge/gravity duality. The main subjects are a) Testing and understanding such dualities by exploring how they work for systems with a lot of supersymmetry b) Constructing and exploring approximate string theory duals of QCD c) Applying gauge/gravity duality to other areas of physics such as condensed matter and nuclear physics. I will briefly discuss the first topic.Comment: 13 pages; Contribution to the proceedings of a symposium celebrating the 80th birthday of Murray Gell-Man

Recent Progress in AdS/CFT

The study of AdS/CFT (or gauge/gravity) duality has been one of the most active and illuminating areas of research in string theory over the past decade. The scope of its relevance and the insights it is providing seem to be ever expanding. In this talk I briefly describe some of the attempts to explore how the duality works for maximally supersymmetric systems.Comment: 11 page

The future of string theory

Prophesy is just for fun. The more useful purpose of the exercise is to identify important issues and to stimulate thought about where they stand and how they might be resolved. The subject areas that are fair game include all of particle physics and cosmology

String Theory: Progress and Problems

String theory builds on the great legacy of Yukawa and Tomonaga: New degrees of freedom and control of the UV are two important themes. This talk will give an overview of some of the progress and some of the unsolved problems that characterize string theory today. It is divided into two parts: (1) Connecting String Theory to the Real World; (2) Gauge Theory/String Theory Duality. Two other major subjects, which I will omit, are Black Holes in String Theory and The Impact of String Theory on Mathematics.Comment: 14 pages; Presented at the Yukawa--Tomonaga Centennial Symposium v2: references adde