Lellouch-Lüscher Relation for Ultracold Few-Atom Systems under Confinement
Jing-Lun Li, Paul S. Julienne, Johannes Hecker Denschlag +1 more
We derive an analog of the Lellouch-Lüscher (LL) relation for few-body bosonic systems, linking few-body scattering loss rates to the energies and widths of the corresponding harmonically trapped few-body states. Three-body numerical simulations show that the LL relation applies across a broad range of interaction strengths and energies and allows the determination of scattering rates within a single partial wave. Our Letter establishes a robust theoretical framework for understanding the role of the finite-volume effect in few-body observables in optical lattice and tweezer experiments, enabling precise determination of multibody scattering rates.
arXiv:2511.11906•Physical Review Letters•Apr 21, 2026•0 citations