. This has been developed into a practical methodology, the Proton And Neutron Approximate Shell-model (PANASh). We review the basic ideas and present recent results. We also discuss some technical developments in calculations.

DOI: 10.48550/arxiv.2504.00273

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N=Z

N=Z

, such as heavy, neutron-rich nuclides. Here we implement a weak entanglement approximation to bipartite configuration-interaction wave functions, approximating low-lying levels by coupling a relatively small number of many-proton and many-neutron states. This truncation scheme, which we present in the context of past approaches, reduces the basis dimension by many orders of magnitude while preserving essential features of nuclear spectra.