Time-Reversal Symmetry-Protected Coherent Control of Ultracold Molecular Collisions

Coherent control of molecular scattering is based on the initial preparation of molecules in a superposition of internal states, creating interfering pathways to manipulate the integral cross section. However, the contributions from different final partial waves add incoherently to the integral cross sections, diminishing the control. This phenomenon, known as partial wave scrambling, presents a major challenge for coherent control of scattering.

In this poster, we show that time-reversal symmetry can mitigate partial wave scrambling. Specifically, by preparing molecules in coherent superpositions of states related by time-reversal symmetry,  full control can be achieved for time-reversal invariant final states, such as the J=0, M=0 rotational state. This approach remains effective regardless of the complexity of the collisional dynamics, including highly anisotropic or chaotic dynamics.