Exploring elastic three-body scattering in ultracold alkali-metal gases

We introduce a coupled-channel method for elastic three-body scattering in systems of identical bosonic alkali-metal atoms. The approach relies on the numerically exact two-body off-the-energy-shell transition matrix, constructed from realistic multichannel molecular interaction potentials that support many bound states. By rigorously accounting for this off-shell structure, the method captures both the short-range physics as well as multichannel couplings characteristic of alkali-metal potentials without resorting to model pseudopotentials. The central output is the complex three-body scattering hypervolume—the three-body analog of the two-body scattering length—which we obtain with controlled and verifiable numerical accuracy. As a realistic benchmark, we apply our framework to spin-polarized potassium-39, performing full coupled-channel three-body scattering calculations and extracting the hypervolume over experimentally relevant conditions. The method is general and transferable to other atomic species and interaction models featuring deep molecular potentials with an arbitrarily large number of bound states.We introduce a coupled-channel method for elastic three-body scattering in systems of identical bosonic alkali-metal atoms. The approach relies on the numerically exact two-body off-the-energy-shell transition matrix, constructed from realistic multichannel molecular interaction potentials that support many bound states. By rigorously accounting for this off-shell structure, the method captures both the short-range physics as well as multichannel couplings characteristic of alkali-metal potentials without resorting to model pseudopotentials. The central output is the complex three-body scattering hypervolume—the three-body analog of the two-body scattering length—which we obtain with controlled and verifiable numerical accuracy. As a realistic benchmark, we apply our framework to spin-polarized potassium-39, performing full coupled-channel three-body scattering calculations and extracting the hypervolume over experimentally relevant conditions. The method is general and transferable to other atomic species and interaction models featuring deep molecular potentials with an arbitrarily large number of bound states.

arXiv:2604.15815Physical Review AAug 31, 20260 citations

Two-body scattering in ultracold dilute atom gases

J. Piili

May 28, 20120 citations

Ultracold three-body collisions and their influence on ultracold quantum gases

James R. Macdonald Labs

May 1, 20060 citations

Long-lived complexes and signatures of chaos in ultracold K2 +Rb collisions

James F. E. Croft, N. Balakrishnan, Brian K. Kendrick

Lifetimes of complexes formed during ultracold collisions are of current experimental interest as a possible cause of trap loss in ultracold gases of alkali-metal dimers. Microsecond lifetimes for complexes formed during ultracold elastic collisions of ${\mathrm{K}}_{2}$ with Rb are reported, from numerically exact quantum-scattering calculations. Thermally averaged lifetimes are compared with those calculated using a simple density-of-states approach, which are shown to be reasonable. This validates the density-of-states approach and suggests that the formation of long-lived complexes is indeed the cause of observed experimental trap loss in ultracold alkali-metal-dimer systems. Long-lived complexes correspond to narrow scattering resonances which we examine for the statistical signatures of quantum chaos, finding that the positions and widths of the resonances are in good agreement with the Wigner-Dyson and Porter-Thomas distributions, respectively.Lifetimes of complexes formed during ultracold collisions are of current experimental interest as a possible cause of trap loss in ultracold gases of alkali-metal dimers. Microsecond lifetimes for complexes formed during ultracold elastic collisions of ${\mathrm{K}}_{2}$ with Rb are reported, from numerically exact quantum-scattering calculations. Thermally averaged lifetimes are compared with those calculated using a simple density-of-states approach, which are shown to be reasonable. This validates the density-of-states approach and suggests that the formation of long-lived complexes is indeed the cause of observed experimental trap loss in ultracold alkali-metal-dimer systems. Long-lived complexes correspond to narrow scattering resonances which we examine for the statistical signatures of quantum chaos, finding that the positions and widths of the resonances are in good agreement with the Wigner-Dyson and Porter-Thomas distributions, respectively.

arXiv:1709.07419Physical Review ADec 18, 201740 citations

Ultracold three-body collisions and their influence on ultracold quantum gases

José Paulo D'Incao

Bulletin of the American Physical SocietyMay 20, 20060 citations

{\mathrm{K}}_{2}

with Rb are reported, from numerically exact quantum-scattering calculations. Thermally averaged lifetimes are compared with those calculated using a simple density-of-states approach, which are shown to be reasonable. This validates the density-of-states approach and suggests that the formation of long-lived complexes is indeed the cause of observed experimental trap loss in ultracold alkali-metal-dimer systems. Long-lived complexes correspond to narrow scattering resonances which we examine for the statistical signatures of quantum chaos, finding that the positions and widths of the resonances are in good agreement with the Wigner-Dyson and Porter-Thomas distributions, respectively.