Igor R. Klebanov, Marcus Spradlin, Anastasia Volovich
Physics Letters B
Abstract It has recently been observed that IIB string theory in the pp-wave background can be used to calculate certain quantities, such as the dimensions of BMN operators, as exact functions of the effective coupling λ ′= λ / J 2 . These functions interpolate smoothly between the weak and strong effective coupling regimes of N =4 SYM theory at large R charge J . In this Letter we use the pp-wave superstring field theory of hep-th/0204146 to study more complicated observables. The expansion of the three-string interaction vertex suggests more complicated interpolating functions which in general give rise to fractional powers of λ ′ in physical observables at weak effective coupling.