Dressing phases of AdS3/CFT2

We determine the all-loop dressing phases of the AdS3/CFT2 integrable system related to type IIB string theory on AdS3×S3×T4 by solving the recently found crossing relations and studying their singularity structure. The two resulting phases present a novel structure with respect to the ones appearing in AdS5/CFT4 and AdS4/CFT3. In the strongly coupled regime, their leading order reduces to the universal Arutyunov–Frolov–Staudacher phase as expected. We also compute their subleading order and compare it with recent one-loop perturbative results and comment on their weak-coupling expansion.