Fine Structure of String Spectrum in AdS(5)xS(5)
  The spectrum of an infinite spinning string in AdS(5) does not precisely match the spectrum of dual gauge theory operators, interpolated to the strong coupling regime with the help of Bethe-ansatz equations. We show that the mismatch is due to interactions in the string sigma-model which cannot be neglected even at asymptotically large 't Hooft coupling. 
K. Zarembo, S. Zieme
hep-th