Testing AdS/CFT at string loops

This article is based on the result obtained in hep-th/0508126 and hep-th/0605080 where we use the IIB light-cone string field theory proposed by Dobashi and Yoneya to compute the one string-loop correction to the energies of two impurity BMN states. We found that the result agrees with the gauge theory prediction at leading order – one-loop in Yang-Mills theory – and that is quite close also at second order in Yang-Mills loops. We furthermore find that the half integer powers in the t'Hooft coupling are absent up to the 7/2 power.