Thermally averaged photoassociation controlled by pure cubic pulse

Highlights: • Time-independent population of photoassociation steered by pure cubic pulse. • The thermally averaged effect changes the population transfer process. • Population aggregation effect appears in near-resonance states. • Population accumulation effect appears in off-resonance states. We investigate theoretically the thermally averaged photoassociation of ${}^{85}\mathrm{Rb}$ atoms steered by the pure cubic pulse at the temperature of 120 $\mu K$. The photoassociation controlled by a typical Gaussian pulse is also calculated for comparison. Compared with the results without the thermally averaged effect, the thermally averaged effect reduces the photoassociaiton efficiency significantly. The Gaussian pulse restricts the photoassociation population in the high weight region of initial states, while the cubic pulse can remove the restriction. The population aggregation effect takes place in the near-resonance vibrational states and the population accumulation effect appears in the off-resonance vibrational states.