Ultracold atoms prepared in excited internal states can escape from the trap through inelastic collisions. A magnetic field can be used to suppress the s-wave loss rate coefficient near an s-wave Feshbach resonance. However, at the temperature of µK the p-wave loss rate coefficient becomes increasingly important as the temperature increases. The unsuppressed p-wave loss rate coefficient can far exceed the suppressed s-wave loss rate coefficient, and severely restricts the reduction of the total loss rate coefficient. We calculate the collision rate coefficients of ultracold 85Rb and 87Rb atoms prepared in excited hyperfine and Zeeman states using the coupled-channel method. We find that in 85Rb(F1 = 3, mF1= 3) + 87Rb(F2 = 1, mF2= −1) and 85Rb(F1 = 2, mF1= −2) + 87Rb(F2 = 2, mF2= −2) there exist broad p-wave Feshbach resonances located near s-wave Feshbach resonances, and find that the s- and p-wave loss rate coefficients can be simultaneously suppressed by a magnetic field in the temperature range from 1 to 30 µK. In particular, for 85Rb(F1 = 3, mF1= 3) + 87Rb(F2 = 1, mF2= −1) the proportion of the s- and p-wave loss rate coefficients in the total loss rate coefficient can be well manipulated by adjusting the magnetic field.
We investigate theoretically the formation of ultracold CsYb molecule in the absolute ground state by full optical control. The laser-assisted self-induced Feshbach resonance takes place when the trap state in the optical lattice is coupled with a rovibrational state of the ground electronic state. The Feshbach molecule is formed in the resonant rovibrational state via an adiabatic population transfer by ramping the frequency of a chirped pulse. Two schemes are designed to prepare the absolute ground-state molecule starting from the Feshbach molecule: a pump-dump scheme controlled by short pulses and a stimulated-Raman-adiabatic-passage (STIRAP) scheme steered by long pulses. The probabilities of converting the Feshbach molecule to the absolute ground state molecule by using the pump-dump and the STIRAP schemes are 16% and 99%, respectively.
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