  Trajectories are a central concept in our understanding of classical
phenomena and also in rationalizing quantum mechanical effects. In this work we
provide a way to determine semiclassical paths, approximations to quantum
averages in phase space, directly from classical trajectories. We avoid the
need of intermediate steps, like particular solutions to the Schroedinger
equation or numerical integration in phase space by considering the system to
be initially in a coherent state and by assuming that its early dynamics is
governed by the Heller semiclassical approximation. Our result is valid for
short propagation times only, but gives non-trivial information on the
quantum-classical transition.

Quantum Physics