The course on String theory is divided into two parts, String theory (5p) and Advanced string theory (5p). The first one is offered in the Master program while the second, more advanced, course is suitable for students who aim at doing a Master thesis (20p or 40p) on a related topic.

Teachers: Docent Gabriele Ferretti and Professor Bengt E.W. Nilsson.

The course String theory begins with an introductory discussion of the fundamental problems encountered when trying to understand our universe in terms of standard (quantum) field theory methods, and how string theory may solve them. String theory is then introduced and some of its properties studied. In particular the conformal field theory formulation, low energy supergravity theories, scattering amplitudes, extra dimensions and how their compactifications are related to observed elementary particles. D-branes and non-perturbative aspects are introduced and the connection to eleven dimensional M-theory briefly explained.

Content: not yet decided (will partly overlap with Chapters 1,2.1-2.2,5.1-5.3,6 of String theory by Bengt EW Nilsson and D-branes by Gabriele Ferretti

Literature: see below and D-branes by Gabriele Ferretti


Advanced string theory is a course introducing more advanced mathematical tools and concepts needed to penetrate deeper into the structure of string/M theory. Loop corrections, partition functions and Riemann surfaces are discussed, together with some recent results connected to gauge theories, AdS/CFT, p-, D-, and M-branes, dualities and the non-perturbative properties of string/M theory.

Content: not yet decided (will partly overlap with Chapters 2,4,5,8,10,11,12 of String theory by Bengt EW Nilsson and D-branes by Gabriele Ferretti
Literature: see below and D-branes by Gabriele Ferretti


Additional literature:
1. M. Green, J. Schwarz and E. Witten, 'Superstring theory', volume I and II (Cambridge university press 1987).
2. J. Polchinski, 'String theory', volume I and II (Cambridge university press 1998).

Index for the courses String theory and Advanced string theory:

Literature: lecture notes
Chapter 1
1.1 Introduction

Chapter 2: The closed uncompactified bosonic string
2.1 Operator product expansions and the Virasoro algebra
2.2 Tree amplitudes and conformal field theory
2.3 One loop amplitudes, partition functions and modular invariance

Chapter 3: The path integral formulation
3.1 Formulation of the problem
3.2 The functional measures
3.3 Tree level amplitudes, the conformal anomaly and the Liouville action
3.4 One loop amplitudes
3.5 Higher genus Riemann surfaces and the Selberg zeta-function

Chapter 4: Reparametrization ghosts
4.1 Determinants and anticommuting ghosts
4.2 The central charge and critical dimensions
4.3 Ghost number and scattering amplitudes
4.4 BRST
4.5 Bosonization of the ghost system

Chapter 5: The compactified closed bosonic string
5.1 Chiral fields and some simple self-dual lattices
5.2 Vertex operators, cocycles, and Kac-Moody algebras
5.3 Interactions in the low energy field theory
5.4 Modular invariance
5.5 The Sugawara construction
5.6 Lattices and their properties
5.7 Theta-functions and lattice partition functions
5.8 Introduction to orbifolds

Chapter 6: The fermionic string

Chapter 7: The covariant lattice approach

Chapter 8: Heterotic strings in four dimensions

Chapter 9: Reggeon formalism, g-loop vacua and the KP hierarchy

Chapter 10: Branes, Maldacena duality and black holes

Chapter 11: Low energy field theories in ten and eleven dimensions

Chapter 12: The non-perturbative structure of string/M theory

Appendix A
A1 Embedding the two sphere in three flat dimensions
A2 Stereographic projections of the two sphere
A3 CP1, Hopf fibration, the Fubini-Study metric and fiber-bundles
A4 Cohomology and Betti numbers
A5 Chern classes
A6 Tangent and line bundles
A7 Kaehler manifolds

Appendix B
B1 Basics in topology
B2 Riemann surfaces
B3 Metrics and structures on Riemann surfaces
B4 Making use of the Riemann-Roch theorem
B5 Homology and the period matrix
B6 Function theory on Riemann surfaces

Appendix C
C1 Genus one modular forms
C2 The Eisenstein series and the holomorphic anomaly
C3 Relation to doubly perioid functions
C4 Relation to quasi periodic functions
C5 Theta functions and prime forms

Appendix D
D1 Super-Riemann surfaces