On quantum corrections to spinning strings and Bethe equations

Recently, it was demonstrated that one-loop energy shifts of spinning superstrings on AdS(5) x S-5 agree with certain Bethe equations for quantum strings at small effective coupling. However, the string result required artificial regularization by zeta-function. Here we show that this matching is indeed correct up to fourth order in effective coupling; beyond, we find new contributions at odd powers. We show that these are reproduced by quantum corrections within the Bethe ansatz. They might also identify the "three-loop discrepancy" between string and gauge theory as an order-of-limits effect. (c) 2005 Elsevier B.V. All rights reserved.