Despite impressive advances in the AdS3/CFT2 correspondence, the setup involving Ramond-Ramond backgrounds, which is related to the D1–D5 system of branes, remained relatively poorly understood. We use the mirror thermodynamic Bethe ansatz (TBA) equations recently constructed by Frolov and Sfondrini to study the spectrum of pure Ramond-Ramond AdS3×S3×T4 strings. We find that the leading-order contribution to the anomalous dimensions at small tension is due to the gapless world-sheet excitations, i.e., to the T4 bosons and their superpartners, whose interactions are nontrivial.
Brollo et al. (Fri,) studied this question.