Time-dependent sampling of the SC-IVR
The semiclassical initial value representation (SC-IVR) uses many classical trajectories to approximate quantum dynamics. Those trajectories can be split into two parts: an easy part to calculate (position and velocities) and a hard part to calculate (the monodromy matrix). Time-dependent importance sampling reduces the total number of expensive trajectories needed by using the easier calculation to filter out trajectories that don’t contribute to the total.