Lecture 04 Apr

Today we discussed the String Theory Landscape.

The Landscape – what’s all the fuss about?

Foci for today:

• Weinberg PRL on cosmological constant and anthropic principle Is there an anthropic bound on cosmological constant (i.e. a “prior” that we exist)? AdS universes () crunch, and deS with too big fly apart before galaxies have a chance to form!
• Explain why there are so many flux vacua in string theory: whither the ? Or is the number of vacua infinite?
• Bousso-Polchinski first string theory realization (J.Polchinski’s Scientific American article on the Landscape)
• KKLT = Kallosh, Kachru, Linde, Trivedi (and then KKLMMT)

But first, here’s the famous peaks and valleys picture.