Nuclear Reactions in Uncharted Territories: Challenges and Opportunities for Theory

Nuclear reaction theory has a long history that is closely linked to developments in quantum science, the achievements of which we are celebrating in 2025. The past couple of decades have seen significant improvements in achieving predictive descriptions of nuclear reactions, due to the combination of sophisticated techniques and powerful computational resources. New experimental facilities provide unprecedented opportunities to probe aspects of nuclear reaction mechanisms that have previously not been accessible. This includes the study of exotic isotopes at radioactive beam facilities and reactions in extreme environments, such as reactions in plasmas produced, e.g., at the National Ignition facility (NIF). I will briefly review recent advances in nuclear reaction theory and present a selection of challenges that remain to be addressed.