RESUMEN
A Feshbach optimized photoassociation (FOPA) process for preparing ultracold excited-state 39K133Cs molecules is studied theoretically. Under the joint action of the magnetic field and short laser pulse, the colliding atoms in a superposition state composed of eight hyperfine components are converted into a molecule in the vibrational level of the excited state via two transition processes, the transition between singlet states and the transition between triplet states. The association efficiency can be significantly enhanced by taking advantage of Feshbach resonance. At different resonance positions, different hyperfine components of the superposition state dominate over the FOPA process, and the quantum interference displays different behaviors. Compared with the FOPA process only including a single hyperfine component, the quantum interference in the FOPA process containing all hyperfine components has a visible effect on the association efficiency.
RESUMEN
We investigate the modulating action of an external electric field on the magnetically tuned Feshbach resonance in ultracold heteronuclear atomic collision by using the multichannel quantum-defect theory (MQDT). The coupling between different partial wave states induced by an electric field is included into the singlet and triplet quantum defect matrices y(0) and y(1). By taking the truncated -C6/R6 - C8/R8 - C10/R10 potential as the reference potential, the threshold behaviors of four quantum-defect parameters for the lowest three partial waves are described. The results calculated by using the MQDT agree with those calculated using the coupled channel method. Moreover, we present an analytical expression used for describing the variation of the position and width of the magnetically tuned Feshbach resonance modulated by an electric field.