An extension of the supersymmetric U model for correlated elctrons is given and integrability is established by demonstrating that the model can be constructed through the Quantum Inverse Scattering Method using an R-matrix without the difference property. Some general symmetry properties of the model are discussed and from the Bethe ansatz solution an expression for the energies is presented.
@article{arxiv.cond-mat/9903274,
title = {Extended integrability regime for the supersymmetric U model},
author = {Jon Links},
journal= {arXiv preprint arXiv:cond-mat/9903274},
year = {2009}
}