In this talk I will present recent results on the Bethe/Gauge correspondence obtained together with Mathew Bullimore and Hee-Cheol Kim. I will describe new ingredients of the Bethe/Gauge dictionary between the XXX Heisenberg spin chain and 2d N = (2,2) supersymmetric gauge theories. In particular, I will show how to construct off-shell Bethe states as orbifold defects in the A-twisted supersymmetric gauge theory and study their correlation functions. It will allow us to include aspects of algebraic Bethe ansatz in the correspondence. In particular, I will show how to interpret spin chain R-matrices as correlation functions of Janus interfaces for mass parameters.

In this talk I will discuss how to construct all solutions consistent with crossing symmetry in the limit of large central charge c ~ N^2, starting from the four-point correlator of the stress tensor multiplet in N=4 SYM. Unitarity forces the introduction of a scale \Delta_{gap} and these solutions organize as a double expansion in 1/c and 1/\Delta_{gap}. These solutions are valid to leading order in 1/c and to all orders in 1/\Delta_{gap} and reproduce, in particular, instanton corrections previously found. Comparison with such instanton computations allows to fix \Delta_{gap}. Using this gap scale one can explain the upper bounds for the scaling dimension of unprotected operators observed in the numerical superconformal bootstrap at large central charge.