On the massless modes of the AdS3/CFT2 integrable systems

Abstract

We make a proposal for incorporating massless modes into the spin-chain of the AdS 3 /CF T 2 integrable system. We do this by considering the α → 0 limit of the alternating δ (2,1;α)2 spin-chain constructed in arXiv:1106.2558. In the process we encounter integrable spin-chains with non-irreducible representations at some of thei r sites. We investigate their properties and construct their R-matrices in terms of Yangians. © 2013 SISSA, Trieste, Italy.