Boundary conditions in charge conjugate sl(N) WZW theories

摘要

We compute the representations (``nimreps'') of the fusion algebra of affinesl(N), which determine the boundary conditions of sl(N) WZW theories twisted bythe charge conjugation. This is done following two procedures, one of generalvalidity, the other specific to the problem at hand. The problem is related tothe classical problem of decomposition of the fundamental representations ofsl(N) onto representations of $B_l=so(2l+1)$ or $C_l =sp(2l)$ algebras. Therelevant nimreps and their diagonalisation matrix are thus expressed in termsof modular data of the affine B or C algebras