From Quantum Scattering to Ultracold Molecules: The Two-Body Lithium-6 System

Ultracold atoms provide a vivid setting to explore quantum mechanics in action. We examine the interaction of two Lithium-6 atoms near a Feshbach resonance as a bridge between basic scattering theory and the formation of ultracold molecules. By incorporating internal spin states, Zeeman coupling, and tunable magnetic fields, we show how key quantum concepts—such as scattering length, bound states, and resonance phenomena—emerge naturally from this two-body system. This approach links fundamental quantum principles to experimentally relevant phenomena in ultracold gases, offering a clear and accessible framework for teaching and outreach. Designed for students and educators, it demonstrates how a simple model captures the essential physics underlying Feshbach resonances and the connection to molecular formation.