  We show that during stochastic beam attenuation in double slit experiments,
there appear unexpected new effects for transmission factors below
$a\lesssim10^{-4}$, which can eventually be observed with the aid of weak
measurement techniques. These are denoted as quantum sweeper effects, which are
characterized by the bunching together of low counting rate particles within
very narrow spatial domains. We employ a "superclassical" modeling procedure
which we have previously shown to produce predictions identical with those of
standard quantum theory. Thus it is demonstrated that in reaching down to ever
weaker channel intensities, the nonlinear nature of the probability density
currents becomes ever more important. We finally show that the resulting
unexpected effects nevertheless implicitly also exist in standard quantum
mechanics.
