2011/04/29 by Zbigniew Idziaszek, Andrea Simoni, Tommaso Calarco +2 · 4 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Dust and Plasma Wave Phenomena #Field (mathematics) #Quantum chaos and dynamical systems #Ultracold atom #Ultracold neutrons #cond-mat.quant-gas #physics.atom-ph
paper · pdf · doi:10.1088/1367-2630/13/8/083005
39 pages, 21 figures
arxiv created 2011/04/29 · openalex publication_date 2011/08/08 · arxiv updated 2015/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We develop an analytical model for ultracold atom–ion collisions using the multichannel quantum-defect formalism. The model is based on analytical solutions of the r −4 long-range potential and on the application of a frame transformation between asymptotic and molecular bases. This approach allows the description of atom–ion interaction in the ultracold domain in terms of only three parameters: the singlet and triplet scattering lengths, assumed to be independent of the relative motion angular momentum, and the lead dispersion coefficient of the asymptotic potential. We also introduce corrections to the scattering lengths that improve the accuracy of our quantum-defect model for higher-order partial waves, a particularly important result for an accurate description of shape and Feshbach resonances at finite temperature. The theory is applied to the system composed of a 40 Ca + ion and a Na atom, and compared with numerical coupled-channel calculations carried out using ab initio potentials. For this particular system, we investigate the spectrum of bound states, the rate of charge-transfer processes and the collision rates in the presence of magnetic Feshbach resonances at zero and finite temperature.