# String Theory

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## Contents

# Contents[edit]

- Introduction
- Supersymmetry
- Two-Dimensional Conformal Field Theory
- String Quantization
- The Free String
- String Interactions
- String Field Theory
- Compactification
- Orbifolds and Orientifolds
- T-Duality
- D-branes
- M-Theory

# Notation[edit]

The metric has signature .

Greek letters from the middle of the alphabet denote coordinates in spacetime. Roman letters taken from the beginning of the alphabet denote coordinates on the worldsheet.

The metric is denoted . In the case where there is a metric of spacetime and a metric of the worldsheet, the worldsheet metric is denoted

A lower-case is the number of dimensions. An upper-class represents the number of spacial dimensions.