Spiky strings in the SL(2) Bethe Ansatz at strong coupling from AdS/CFT

Abstract

We study spiky strings in the context of the SL(2) Bethe ansatz equations. We find an asymmetric distribution of Bethe roots along one cut that determines the all loop anomalous dimension at leading and subleading orders in a large S expansion. At leading order in strong coupling (large lambda) we obtain that the energy of such states is given, in terms of the spin S and the number of spikes n by E-S=n sqrt{lambda}/(2 pi) (ln 16 pi S/(n sqrt{lambda})+ ln sin (pi/n) - 1)+ O(ln S/S). This result matches perfectly the same expansion obtained from the known spiky string classical solution. We then discuss a two cut spiky string Bethe root distribution at one-loop in the SL(2) Bethe ansatz. In this case we find a limit where n goes to infinity, keeping (E+S)/n^2, (E-S)/n, J/n fixed. This is the one loop version of a limit previously considered in the context of the string classical solutions in AdS5 x S5. In that case it was related to a string solution in the AdS pp-wave background.