Emergent phenomena in nuclei: Collectivity and clustering within an ab initio framework*

Remarkable progress in {\it ab initio} nuclear theory has opened up new domains of the nuclear chart for study and prediction. In this talk, I will discuss two central questions, namely, understanding and predicting diverse nuclear properties from the underlying physics of only two or three nucleons, and the origin of emergent orderly patterns in the intricate nuclear dynamics. In particular, I will address a long-standing challenge, namely, the emergence from first principles of collectivity and clustering in light to  medium-mass nuclei, with implications for  reproducing enhanced E2 transitions without effective charges; for the formation of alpha clustering; as well as for the description of alpha-capture reactions of interest to nucleosynthesis. This is achieved by using physically relevant  degrees of freedom including the symmetry-adapted basis framework, which exploits approximate symmetries that, we find, dominate the nuclear dynamics. These new developments,  empowered by high performance computing, are key to further advancing  our knowledge about astrophysical processes and fundamental symmetries in nature,  as well as related reactions, providing complementary theory to experimental research at radioactive beam facilities.