Erratum: The open XXZ chain at Δ= -1/2 and the boundary quantum Knizhnik-Zamolodchikov equations (Journal of Statistical Mechanics: Theory and Experiment (2021) (013104) DOI: 10.1088/1742-5468/abd028)

The open XXZ spin chain with the anisotropy parameter "=-12 and diagonal boundary magnetic fields that depend on a parameter x are studied. For real x > 0, the exact finite-size ground-state eigenvalue of the spin-chain Hamiltonian is explicitly computed. In a suitable normalisation, the ground-state components are characterised as polynomials in x with integer coefficients. Linear sum rules and special components of this eigenvector are explicitly computed in terms of determinant formulas. These results follow from the construction of a contour-integral solution to the boundary quantum Knizhnik-Zamolodchikov equations associated with the R-matrix and diagonal K-matrices of the six-vertex model. A relation between this solution and a weighted enumeration of totally-symmetric alternating sign matrices is conjectured.