title: Pseudopotential analog for zero-range photoassociation and Feshbach resonance.
abstract: A zero-range approach to atom-molecule coupling is developed in analogy to the Fermi-Huang pseudopotential approach to collisions. It is shown by explicit comparison to an exactly solvable finite-range model that replacing the molecular bound-state wave function with a regularized delta function can reproduce the exact scattering amplitude in the long-wavelength limit. Using this approach, we find an analytical solution to the two-channel Feshbach resonance problem for two atoms in a spherical harmonic trap, highlighting the strong dependence of the effective scattering length and bare-molecule population on the atom-molecule coupling strength.
authors.affiliation: Department of Physics and Astronomy, Ohio University, Athens, 45701, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Moore