Emergent clustering phenomena in the framework of the ab initio symmetry-adapted no-core shell model

Abstract

This article discusses the emergence – from first principles – of collectivity and clustering in light and intermediate-mass nuclei, up to the calcium region, with implications for reproducing enhanced E2 transitions in deformed nuclei, and for further understanding the formation of alpha clustering. Structure calculations use nucleon-nucleon chiral potentials and are based on the ab initio symmetry-adapted no-core shell model (SA-NCSM) that expands the reach of the no-core shell-model theory to heavier nuclei and enables the description of spatially enhanced nuclear configurations. This is achieved by using a physically relevant symmetry-adapted basis, which exploits approximate symmetries that, we find, dominate the nuclear dynamics. Important implications that have deepened our understanding of emergent phenomena in nuclei, such as enhanced collectivity, giant resonances, pairing, and clustering, are discussed for Be, C, O, Ne, and Ti isotopes.