TBA

We determine the bosonic part of the superstring sigma model Lagrangian on eta-deformed AdS_5 x S^5, and use it to compute the perturbative world-sheet scattering matrix of bosonic particles of the model. We then compare it with the large string tension limit of the q-deformed S-matrix and find exact agreement. We comment on the structure of the RR sector of the type IIB SUGRA background.

We discuss the Zamolodchikov-Faddeev algebra for the superstring sigma-model on AdS5 x S5. We find the canonical su(2,2)2 invariant S-matrix satisfying the standard Yang-Baxter and crossing symmetry equations. Its near-plane-wave expansion matches exactly the leading order term recently obtained by the direct perturbative computation. We also show that the S-matrix obtained by Beisert in the gauge theory framework does not satisfy the standard Yang-Baxter equation, and, as a consequence, the corresponding ZF algebra is twisted. The S-matrices in gauge and string theories however are physically equivalent and related by a non-local transformation of the basis states which is explicitly constructed.

We consider classical strings propagating in a background generated by a sequence of TsT transformations. We describe a general procedure to derive the Green-Schwarz action for strings. We show that the U(1) isometry variables of the TsT-transformed background are related to the isometry variables of the initial background in a universal way independent of the details of the background. This allows us to prove that strings in the TsT-transformed background are described by the Green-Schwarz action for strings in the initial background subject to twisted boundary conditions. Our construction implies that a TsT transformation preserves integrability properties of the string sigma model. We discuss in detail type IIB strings propagating in the TsT-transformed AdS(5) x S(5) space-time and find the twisted boundary conditions for bosons and fermions. We also discuss string zero modes whose dynamics is governed by a fermionic generalization of the integrable Neumann model.