Contributor info: Dr Luke Corcoran

Luke Corcoran, Marius de Leeuw

SciPost Phys. Core 7, 045 (2024) · published 26 July 2024 | Toggle abstract · pdf

We complete the classification of 4×4 regular solutions of the Yang-Baxter equation. Apart from previously known models, we find four new models of non-difference form. All the new models give rise to Hamiltonians and transfer matrices that have a non-trivial Jordan block structure. One model corresponds to a non-diagonalisable integrable deformation of the XXX spin chain.