  Quantum trajectories defined in the de Broglie--Bohm theory provide a causal
way to interpret physical phenomena. In this Letter, we use this formalism to
analyze the short time dynamics induced by unstable periodic orbits in a
classically chaotic system, a situation in which scars are known to play a very
important role. We find that the topologies of the quantum orbits are much more
complicated than that of the scarring and associated periodic orbits, since the
former have quantum interference built in. Thus scar wave functions are
necessary to analyze the corresponding dynamics. Moreover, these topologies
imply different return routes to the vicinity of the initial positions, and
this reflects in the existence of different contributions in each peak of the
survival probability function.
