The all-loop integrable spin-chain for strings on AdS_3 x S^3 x T^4: the massive sector

TL;DR

This paper constructs an all-loop integrable S-matrix for the massive sector of string theory on AdS_3 x S^3 x T^4, providing a new Bethe Ansatz and matching recent perturbative results.

Contribution

It introduces a novel all-loop S-matrix for the massive modes of the AdS_3 x S^3 x T^4 string, including new crossing equations and a revised Bethe Ansatz.

Findings

Derived the all-loop dynamic S-matrix for the massive sector.

Formulated crossing equations for the dressing phases.

Presented a Bethe Ansatz consistent with recent perturbative data.

Abstract

We bootstrap the all-loop dynamic S-matrix for the homogeneous psu(1,1|2)^2 spin-chain believed to correspond to the discretization of the massive modes of string theory on AdS_3 x S^3 x T^4. The S-matrix is the tensor product of two copies of the su(1|1)^2 invariant S-matrix constructed recently for the d(2,1;alpha)^2 chain, and depends on two antisymmetric dressing phases. We write down the crossing equations that these phases have to satisfy. Furthermore, we present the corresponding Bethe Ansatz, which differs from the one previously conjectured, and discuss how our construction matches several recent perturbative calculations.