‘String Theory and M-Theory ; AModern Introduction’

String theory is one of the most exciting and challenging areas of modern
theoretical physics. It was developed in the late 1960s for the purpose of describing the strong nuclear force. Problems were encountered that prevented
this program from attaining complete success. In particular, it was realized
that the spectrum of a fundamental string contains an undesired massless
spin-two particle. Quantum chromodynamics eventually proved to be the
correct theory for describing the strong force and the properties of hadrons.
New doors opened for string theory when in 1974 it was proposed to identify
the massless spin-two particle in the string’s spectrum with the graviton, the
quantum of gravitation. String theory became then the most promising candidate for a quantum theory of gravity unified with the other forces and has
developed into one of the most fascinating theories of high-energy physics.
The understanding of string theory has evolved enormously over the years
thanks to the efforts of many very clever people. In some periods progress
was much more rapid than in others. In particular, the theory has experienced two major revolutions. The one in the mid-1980s led to the subject
achieving widespread acceptance. In the mid-1990s a second superstring
revolution took place that featured the discovery of nonperturbative dualities that provided convincing evidence of the uniqueness of the underlying
theory. It also led to the recognition of an eleven-dimensional manifestation, called M-theory. Subsequent developments have made the connection
between string theory, particle physics phenomenology, cosmology, and pure
mathematics closer than ever before. As a result, string theory is becoming
a mainstream research field at many universities in the US and elsewhere.
Due to the mathematically challenging nature of the subject and the
above-mentioned rapid development of the field, it is often difficult for someone new to the subject to cope with the large amount of material that needs
to be learned before doing actual string-theory research. One could spend
several years studying the requisite background mathematics and physics,
but by the end of that time, much more would have already been developed,
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and one still wouldn’t be up to date. An alternative approach is to shorten
the learning process so that the student can jump into research more quickly.
In this spirit, the aim of this book is to guide the student through the fascinating subject of string theory in one academic year. This book starts with
the basics of string theory in the first few chapters and then introduces the
reader to some of the main topics of modern research. Since the subject is
enormous, it is only possible to introduce selected topics. Nevertheless, we
hope that it will provide a stimulating introduction to this beautiful subject
and that the dedicated student will want to explore further.
The reader is assumed to have some familiarity with quantum field theory
and general relativity. It is also very useful to have a broad mathematical
background. Group theory is essential, and some knowledge of differential
geometry and basics concepts of topology is very desirable. Some topics in
geometry and topology that are required in the later chapters are summarized in an appendix