Isospin-symmetry restoration within the nuclear density functional theory: Formalism and applications

Isospin symmetry of atomic nuclei is explicitly broken by the charge-dependent interactions, primarily the Coulomb force. Within the nuclear density functional theory, isospin is also broken spontaneously. We propose a projection scheme rooted in a Hartree-Fock theory that allows the consistent treatment of isospin breaking in both ground and exited nuclear states. We demonstrate that this scheme is free from spurious divergences plaguing particle-number and angular-momentum restoration approaches. Applications of the new technique include excited high-spin states in medium-mass N=Z nuclei, such as superdeformed bands and many-particle–many-hole terminating states. Owing to the large spin polarization and/or high seniority of these states, pairing correlations have been ignored.