Long-time and unitary properties of semiclassical initial value representations

摘要

We numerically compare the semiclassical "frozen Gaussian" Herman-Kluk propagator [Chem.Phys.91,27 (1984)] and the [thawed Gaussian" propagator put forward recently by Baranger et al.[J.Phys.A 34,7227 (2001)] by studing the quantum dynamics in some nonlinear one-dimensional potentials.The resons for the lack of long-time accuracy and norm conservation in the latter method are uncovered.We amend the thawed Gaussian propagator with a global harmonic approximation for the stability of trajectories and demonstrate that this revised propagator is a true alternative to the herman-Kluk propagator with simiar accuracy.