Generalized Superconformal Index for Three Dimensional Field Theories
  We introduce a generalization of the S^2 x S^1 superconformal index where background gauge fields with magnetic flux are coupled to the global symmetries of the theory. This allows one to gauge a global symmetry at the level of the index, which we use to show the matching of the superconformal index for N=2 SQED with N_f flavors and its mirror dual. 
Anton Kapustin, Brian Willett
hep-th