Soft question: What are the many techniques in string theory to eliminate extra dimensions?

Question

There are a variety of ways in which string theory avoids extra dimensions, the most popular of which is obviously compactification, but there are some other less popular approaches (non-critical strings, etc.) as well. Perhaps it would be a good idea to collate such approaches found in the literature, in the answer thread here?

Comments

Feel free to move this to chat if you feel it's inappropriate on the main site.

Answer 1

Let me start with the well-known ones:

• Standard compactification on Calabi-Yau or G(2) manifolds, probably the most popular
• "Large Extra Dimensions" (see this for a critique)
• The Randall-Sundrum model
• Non-critical string theory - by introducing an additional "Liouville field"
• This variant of the Nambu-Goto action with an infinite number of extra terms