Introduction to string theory and string compactifications

DEVELOPMENT IN STRING THEORY

The string theory is a fast moving subject, both physics wise and in the respect of mathematics. In order to keep up with the discipline it is important to move with new ideas which are being stressed. Here I wish to give extracts from new papers of ideas which I have recently found interesting. There are six papers which are involved: I ."Strings formulated directly in 4 dimensions " A. N...

Introduction to String Theory

We give a pedagogical introduction to string theory, D-branes and p-brane solutions. 1 Introductory remarks These notes are based on lectures given at the 271-th WE-Haereus-Seminar ‘Aspects of Quantum Gravity’. Their aim is to give an introduction to string theory for students and interested researches. No previous knowledge of string theory is assumed. The focus is on gravitational aspects and...

INTRODUCTION to STRING FIELD THEORY

Accelerating cosmologies from M/String theory compactifications

We point out that the solution of (4 + n)-dimensional gravity coupled to the dilaton and an n-form field strength can give rise to a flat 4-dimensional universe (with a scale factor) of the type proposed recently under time dependent compactifications. The compact internal spaces could be hyperbolic, flat or spherical and the solution is identical to the space-like two brane or S2-brane. We sho...

(0,2) String Compactifications

Using the simple current method we study a class of (0, 2) SCFTs which we conjecture to be equivalent to (0, 2) σ models constructed in the framework of gauged linear sigma models.