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Instantons in N=2 4d Theories with Defects and Integrability
  OKC/Nordita High-Energy Physics Theory seminar

Monday 07 April 2014
from 13:30 to 15:00
at 122:026
Speaker : Andrey Zayakin (Universidade de Santiago de Compostella)
Abstract : We consider an extension of the duality between N=2 field theories in 4d and integrable theories in 2d by adding a codimension 2 defect, described by its Gukov-Witten parameters. Viewed from the Alday-Gaiotto-Tachikawa prospective, the duality relates now the correlators in an affine SL(N)-algebra CFT (Wess-Zumino-Witten model) rather than those of a W_N (Toda/Liouville model) to the partition function and observables in 4d. Viewed from the sigma-model prospective, the theory with defect is dual now to a Bethe Ansatz with some extra twist parameters. We consider the extended duality from these both points of view. A nice represenation-theoretic understanding of the instantonic partition function with the extra parameters is suggested. We comment on the relation between the localization calculation of a Wilson loop in 4d with defects and the CFT calculation thereof. We suggest a modified Yang-Yang function for the 2d-4d duality, where twists are simply related to Gukov-Witten parameters. Basing on the modified Yang-Yang function, we study the marginal stability curves for N=2 SQCD with defects. All these findings point out a fruitful and interesting direction in the studies of the 4d-2d duality.

Nordita  | Last modified 03 April 2014 15:13  |  HELP