QUANTUM ALGEBRAIC DESCRIPTION OF THE PAIRING CORRELATIONS IN A SINGLE-J NUCLEAR SHELL

Pairing in a single-j shell is described in terms of two Q-oscillators , one describing the J = 0 fermion pairs and the other corresponding t o the J not-equal 0 pairs, the deformation parameter T = ln Q being re lated to the inverse of the size of the shell. Using these two oscilla tors an SU(Q)(2) algebra is constructed, while a pairing Hamiltonian g iving the correct energy eigenvalues up to terms of first order in the small parameter can be written in terms of the Casimir operators of t he algebras appearing in the U(Q)(2) superset-of U(Q)(1) chain, thus e xhibiting a quantum algebraic dynamical symmetry. The additional terms introduced by the Q-oscillator are found to improve the agreement wit h the experimental data for the neutron pair separation energies of th e Sn isotopes, with no extra parameter introduced.