Landscape Architecture

Readers of Lee Smolin's The Trouble With Physics will recall that the whole string theory landscape problem depends on flux compactification. I probably can't be trusted to explain it correctly, but the trouble starts with the fact that you need to curl up six of the space dimensions of ten dimensional spacetime. Once one has done this with Calabi-Yau manifolds, you have two more problems: They don't naturally lend themselves to a positive cosmological constant (which we observe) and they seem likely to spontaneously self-destruct.

A way was found to stabilize them with tape and baling wire, or, more technically, electric and magnetic flux bound to branes. A lot of ways. Say 10^350. Kachru and Douglas, the inventors, have a new Reviews of Modern Physics article: hep-th/0610102 on the subject, and Peter Woit has some commentary. The article has at least some elementary parts, and Peter's commentary is interesting. So are the responses in his comment section.

Opinions remain divided as to whether a)the landscape really exists and b)whether anything can be deduced from it if it does.

Epicycles! We need more epicycles!

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