PP-wave/CFT2 duality

We investigate the pp-wave limit of the AdS3xS3xK3 compactification of type-IIB string theory from the point of view of the dual SymN(K3) CFT. It is proposed that a fundamental string in this pp-wave geometry is dual to the c=6 effective string of the SymN(K3) CFT, with the string bits of the latter being composed of twist operators. The massive fundamental string oscillators correspond to certain twisted Virasoro generators in the effective string. It is shown that both the ground states and the genus expansion parameter (at least in the orbifold limit of the CFT) coincide. Surprisingly the latter scales like J2/N rather than the J4/N2 which might have been expected. We demonstrate a leading-order agreement between the pp-wave and CFT particle spectra. For a degenerate special case (one NS 5-brane) an intriguing complete agreement is found. (author)