From nuclear structure to time-dependent dynamics

The exponential decay of unstable states is one of the most pervasive and well-studied phenomena in physics, yet its quantum-mechanical foundations remain obscure in several important respects. Exponential decay is not a straightforward consequence of quantum dynamics; rather, it arises from a subtle equilibrium involving a resonant state with a decaying amplitude, shaped by the interplay between outgoing radiation and internal dynamics. A deeper understanding requires careful attention to the early- and late-time behavior of the system, especially in the case of  near-threshold nuclear states.

 

Unlike bound states, resonant states retain a “memory” of their formation, including non-resonant background contributions and quantum entanglement. Their decaying wave functions remain influenced by internal dynamics, leading to complex, non-exponential, and sometimes noisy decay behavior. These features reveal nuanced transient stages between distinct decay regimes, offering deeper insight into underlying nuclear structure and reactions from a time-dependent perspective.

 

This talk will highlight recent theoretical and experimental efforts to investigate nuclear structure through complex decay processes. Emphasis will be placed on novel methodologies for probing near-threshold behavior and transient phenomena, as well as on identifying observables and developing physical interpretations of near-threshold nuclear structure. The discussion will be supported by realistic nuclear examples and experimental data.