  A complete theoretical treatment in many problems relevant to physics,
chemistry, and biology requires considering the action of the environment over
the system of interest. Usually the environment involves a relatively large
number of degrees of freedom, this making the problem numerically intractable
from a purely quantum-mechanical point of view. To overcome this drawback, a
new class of quantum trajectories is proposed. These trajectories, based on the
same grounds as Bohmian ones, are solely associated to the system reduced
density matrix, since the evolution of the environment degrees of freedom is
not considered explicitly. Within this approach, environment effects come into
play through a time-dependent damping factor that appears in the system
equations of motion. Apart from their evident computational advantage, this
type of trajectories also results very insightful to understand the system
decoherence. In particular, here we show the usefulness of these trajectories
analyzing decoherence effects in interference phenomena, taking as a working
model the well-known double-slit experiment.
