Exact boson mapping of the nuclear pairing Hamiltonian
An exact boson mapping of the deformed mean-field plus equal strength pairing Hamiltonian is considered. In the mapping, fermion pair operators are mapped exactly to the corresponding bosons. The mapping occurs at the level of the Richardson-Gaudin equations. The image of the mapping results is a Bose-Hubbard model with level-dependent hopping. Although the resultant Bose-Hubbard Hamiltonian is non-Hermitian, a part of spectrum of the Bose-Hubbard Hamiltonian with U/t = 1 determined by the corresponding Richardson-Gaudin (Bethe ansatz) equations corresponds exactly to the whole spectrum of the pairing Hamiltonian. © 2009 IOP Publishing Ltd.