*Post by Zaz*Thanks to those picking up this thread. I want to recall that

the intent is to collect LISTS OF QUESTIONS -- to be answered later

(the answers will be entire threads of their own, I imagine).

1. Be concise.

2. Be specific.

3. Refrain from editorializing.

These apply to moderators and posters alike.

Thanks, and I look forward to reading more FAQ's.

I'll give it a try. I have taken your original questions and incorporated

them in the following tentative proposal for a rough outline of a list of

possible FAQs that currently come to my mind. Even though this list looks

long, I am certain to have forgotten lots of important points. The

formatting also needs some more work. And probably there is some

repetition, too.

Anyway, here goes:

1. Why string theory?

1.1 What problems are there with non-stringy fundamental physics?

1.1.1 Why does gravity have to be quantized?

1.1.2 What is the problem with quantizing gravity?

1.1.3 What are effective field theories and is the standard model one?

1.1.4 Why is the standard model thought to be "not the last word"?

1.1.5 What is (are) the hierarchy problem(s)?

1.1.6 Why is susy considered an attractive idea?

1.1.7 What is the cosmological constant problem?

1.2 How does string theory shed light on the problems with non-stringy

fundamental physics?

1.2.1 How does gravity arise in string theory?

1.2.2 How do branes arise in string theory?

1.2.3 How does Yang-Mills theory arise in string theory?

1.2.4 How does supersymmetry arise in string theory?

1.2.5 In which sense does string theory unify gravity with gauge forces

as well as forces with matter?

1.2.5 How are standard-model-like models found inside string theory?

1.2.6 How does AdS/CFT help to understand ordinary QCD?

1.2.7 Does string theory help with the cosmological constant problem?

1.2.8 Is perturbative string theory sufficient to address issues in

cosmology?

1.3 How can string theory be motivated from ordinary field theory?

1.3.1 What did historically lead to string theory?

1.3.2 What is the "worldline formalism" in field theory?

1.3.3 What replaces Feynman diagrams in string theory?

1.3.4 How is the Klein-Gordon action like 1D gravity coupled to scalar

fields on the worldline?

1.3.5 How is it that ordinary fermions have N=1 SUSY on their worldline?

1.3.6 How does field theory compare to string field theory?

1.3.7 Can we consider even higher-dimensional objects than strings?

2. What are the principles of string theory?

2.1 What are the Polyakov and the Nambu-Goto actions?

2.2 Why conformal invariance?

2.3 What is the BRST formalism?

2.4 What is the spectrum of the string?

2.5 How can we think of particles as being strings?

2.6 What is the difference between the Planck scale and the string

scale ?

2.6 Why does one consider 10 dimensional backgrounds?

2.7 Where do the background equations of motion come from?

2.9 How do D-branes follow from strings?

2.10 What is the Dirac-Born-Infeld action?

2.11 What is the meaning of the tachyon?

2.12 Why do we need worldsheet supersymmetry?

2.13 Why do there appear to be five different "string theories"?

2.14 What did Green and Schwarz do?

2.15 What are dualities?

2.16 How does the eleventh dimension come into the game?

2.17 What is meant by "M-theory"?

2.18 What is Matrix Theory?

2.19 What is String Field Theory?

2.20 What is AdS/CFT?

2.21 What are *the* equations of string theory?

3. What are the implications of string theory?

3.1 What are the experimental consequences of string theory?

3.1.1 What does string theory predict?

3.1.2 How could string theory be tested?

3.1.3 What would happen when a realistic string vacuum were found?

3.1.4 What does string theory say about cosmology?

3.1.5 What is the vacuum selection problem?

3.1.6 What is meant by the "landscape"?

3.2 What impact does string theory have on general theoretical physics?

3.2.1 What is meant by "embedding" a field theory in string theory?

3.2.2 What can be learned about ordinary field theories from string

dualities?

3.2.3 What does AdS/CFT teach us about ordinary field theories?

3.2.4 What is the twistor string formalism and what is it good for?

3.2.5 What does string theory say about black hole entropy?

3.2.6 What is meant be "holography" in string theory?

3.2.7 What is the topological string and what is it good for?

3.2.8 What is meant by "topological M-theory"?

3.3. What is the interplay between string theory and pure mathematics?

3.3.1 What are index theorem and their relation to ST?

3.3.2 What is mirror symmetry and its relation to ST?

3.3.3 What is the monster group and its relation to ST?

3.3.4 What is K-theory and its relation to ST?

3.3.5 What are derived categories and their relation to ST?

3.3.6 What are Kac-Moody algebras and their relation to ST?

4. What are the big open questions in string theory?

4.1 What is known about the non-perturbative definition of the theory?

4.2 What is string theory, really?

4.3 How can I read all of today's papers before lunch?