  We study a one-dimensional system of spatially extended particles, which are
fixated to regularly spaced locations by means of elastic springs. The
particles are assumed to be driven by a Gaussian noise and to have dissipative,
energy-conserving or anti-dissipative (flipper-like) interactions, when the
particle density exceeds a critical threshold. While each particle in
separation shows a wellbehaved behavior characterized by a Gaussian velocity
distribution, the interaction of particles at high densities can cause an
avalanche-like momentum and energy transfer, which can generate steep power
laws without a well-defined variance and mean value. Specifically, the velocity
variance increases dramatically towards the free boundaries of the
driven-many-particle system. The model might also have some relevance for a
better understanding of crowd disasters. Our results suggest that these are
most likely caused by passive momentum transfers, and not by active pushing.
