Coherent Control of Ultracold Molecular Collisions: The Role of Resonances

We consider the coherent control of ultracold molecule-molecule scattering, impacted by a dense set of rovibrational resonances. To characterize the resonance spectrum, a rudimentary model based on multichannel quantum defect theory has been used to study the control of the scattering cross section and the reaction rate. Complete control around resonance energies is shown to be possible, but thermal averaging over a large number of resonances significantly reduces the extent of control of reaction rates related to the random distribution of optimal control parameters between resonances. We show that measuring the extent of coherent control could be used to extract meaningful information about the relative contribution of direct scattering versus collision complex formation, as well as about the statistical regime.

Automated summary

This study investigates the coherent control of ultracold molecule-molecule scattering influenced by a dense set of rovibrational resonances. A simple model based on multichannel quantum defect theory is used to characterize the resonance spectrum and analyze the control of scattering cross section and reaction rate. The results show that complete control is possible around resonance energies, but thermal averaging reduces the control range of reaction rates due to the random distribution of optimal control parameters among resonances. Measuring the extent of coherent control can provide meaningful information about the relative contribution of direct scattering versus collision complex formation and the statistical regime.