Characterization, quantification and control of entanglement generated by bimolecular collisions

Interactions between molecules naturally give rise to entanglement, a key resource for quantum computation, sensing, and communication. Among these interactions, bimolecular inelastic scattering and chemical reactions stands out as a fundamental mechanism for creating entangled states. This talk introduces a theoretical framework designed to quantitatively explore the types and amounts of entanglement produced during molecular collisions and chemical reactions.

Coupling between the external (motional) and internal degrees of freedom of colliding molecules leads inelastic scattering to generate a rich variety of classes of entanglement, including discrete-variable–discrete-variable (DV–DV), continuous-variable–continuous-variable (CV–CV), and hybrid discrete-variable–continuous-variable (DV–CV) entanglement. After introducing and characterizing these distinct classes of entanglement, we focus on the hybrid DV–CV entanglement. The formalism is illustrated using three representative systems: Rb–Sr⁺ scattering, SrF–Rb scattering, and the chemical reaction F + HD. We show that chemical reactions are particularly effective for generating large DV–CV entanglement in the reaction products. Moreover, we demonstrate that the degree of DV–CV entanglement can be efficiently tuned using external magnetic fields, exhibiting pronounced variations in the vicinity of Feshbach resonances.