Divide, project, recouple: accelerating beyond-mean-field calculations

One approach to the nuclear many-body problem is the generator coordinate method (and related beyond-mean-field approaches). In that method, one generates a nonorthogonal basis of reference states, for example through constrained mean-field calculations, projecting out good quantum numbers such as angular momentum. While capturing essential physics, computing with large numbers of reference states leads to a heavy computational burden. Here I apply a recently implemented method (Gorton and Johnson, PRC 110, 034305 (2024)) : I split off the many-proton and many-neutron components, project good angular momentum independently, and then recouple. This leads to significantly improved results for very little additional computational cost, and may be a good approach for heavy nuclides beyond the scope of the traditional nuclear shell model.