| DATE: |
2009-01-20 11:00 - 12:00 |
| PLACE: |
Kenkyu Honkan 2F RM 220 |
| TITLE: |
Twistor Strings, Pure Spinors, and N=2 Superstrings |
| CONTACT: |
HIKIDA Yasuaki |
| SPEAKER: |
Dr. Mohab Abou Zeid (Queen Mary, University of London) |
| ABSTRACT: |
Different string theories have been proposed to describe N=4 super Yang-Mills theory at weak coupling, while others are known to describe a self-dual form of this theory and of Einstein supergravity. The original twistor strings of Witten and of Berkovits contain the higher derivative N=4 conformal supergravity, however modifications of these theories give various twistor strings with the spectrum of super Yang-Mills coupled to Einstein supergravity (including one with the spectrum of N=8 supergravity, two with the spectrum of N=4 supergravity coupled to N=4 super Yang-Mills, a family of N>0 models with the spectra of self-dual supergravity coupled to self-dual super Yang-Mills, and an N=0 string with the spectrum of self-dual gravity coupled to self-dual Yang-Mills and a scalar). An open string with the spectrum of self-dual N=4 super Yang-Mills was constructed by Berkovits, and the target space for this theory is an (x,theta) space related to the dimensional reduction of the ten dimensional pure spinor formulation of the superstring. The string with N=2 local world-sheet supersymmetry describes self-dual Yang-Mills and self-dual Einstein gravity in 2+2 dimensions, and Siegel has argued that requiring Lorentz invariance of the theory implies its equivalence to an N=4 string which describes self-dual N=4 super Yang-Mills and N=8 self-dual supegravity. The connections between these string-theoretic approaches to perturbative super Yang-Mills and supergravity will be discussed, using the Berkovits-Vafa embedding mechanism as a unifying principle. |
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