  We discuss the notion of an effective, average, quantum mechanical path which
is a solution of the dynamical equations obtained by extremizing the quantum
effective action. Since the effective action can, in general, be complex, the
effective path will also, in general, be complex. The imaginary part of the
effective action is known to be related to the probability of particle creation
by an external source and hence we expect the imaginary part of the effective
path also to contain information about particle creation. We try to identify
such features using simple examples including that of effective path through
the black hole horizon leading to thermal radiation. Implications of this
approach are discussed.
