Abstract. A pairing model for nucleons, introduced by Richardson in 1966, which describes proton–neutron pairing as well as proton–proton and neutron–neutron pairing, is re-examined in the context of the quantum inverse scattering method. Specifically, this shows that the model is integrable by enabling the explicit construction of the conserved operators. We determine the eigenvalues of these operators in terms of the Bethe ansatz, which in turn leads to an expression for the energy eigenvalues of the Hamiltonian.

PACS numbers: 03.65.Fd, 31.15.Hz, 02.30.Ik

Print publication: Issue 30 (2 August 2002)
Received 14 May 2002
Published 19 July 2002